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Glacial Hazards and Avalanches in High Mountains of Nepal Himalaya


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This paper provides a comprehensive overview of the glacial hazards (GHs) and reflects the situations in the Nepal Himalaya. We discuss on the different GHs with focus on the avalanches (snow, ice, and rock), presenting a nation-wide database on avalanches compiled from literature. We also share the relevant policies in the GHs and lays groundwork for future research on the high-altitude hazards. GHs are prone to high mountains of Nepal, yet it is startling that the area has received the least priority. Almost every year, human casualties and property losses reported due to various disastrous events in the country. We documented 60 avalanche events since the 1920s across the country, ensuing the loss of more than 370 human lives. Almost all high-altitude regions of Nepal are prone to avalanches. Number of avalanche events and casualties were the highest in the Khumbu region of Nepal. In recent years, the avalanche records and casualties are also expanding in other parts of the country, most likely due to increased human activities at high altitude regions and documentation. It is inevitable to analyze the hazards prevalent in the mountains to ensure safe and secure livelihood, trekking, and mountaineering activities. We also underline the urgent research priorities to provide a more systematic understanding of GHs in Nepal.
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Journal of Tourism and Himalayan Adventures, Vol. 2 ISSN: 2717-5030 (Print) 2738-9642 (Online)
Glacial... | 87
This paper provides a comprehensive overview of the glacial hazards (GHs) and reects the
situations in the Nepal Himalaya. We discuss on the different GHs with focus on the
avalanches (snow, ice, and rock), presenting a nation-wide database on avalanches compiled
from literature. We also share the relevant policies in the GHs and lays groundwork for future
research on the high-altitude hazards. GHs are prone to high mountains of Nepal, yet it is
startling that the area has received the least priority. Almost every year, human casualties and
property losses reported due to various disastrous events in the country. We documented 60
avalanche events since the 1920s across the country, ensuing the loss of more than 370 human
lives. Almost all high-altitude regions of Nepal are prone to avalanches. Number of avalanche
events and casualties were the highest in the Khumbu region of Nepal. In recent years, the
avalanche records and casualties are also expanding in other parts of the country, most likely
due to increased human activities at high altitude regions and documentation. It is inevitable
to analyze the hazards prevalent in the mountains to ensure safe and secure livelihood,
trekking, and mountaineering activities. We also underline the urgent research priorities to
provide a more systematic understanding of GHs in Nepal.
Keywords: Mountain Hazards, Avalanche, Snowstorm, GLOFs, Rock fall
Mountains across the globe have been the most interesting places for the trekking and
mountaineering adventure tourism (Thakuri & Koirala, 2019; Mu & Nepal, 2016). Further,
most mountains serve as the important sources of water as they store water in the form of
Sudeep Thakuri, PhD*
Associate Professor, Central Department of Environmental Science, Tribhuvan University
*Corresponding author's e-mail:
Raju Chauhan
Visiting Faculty, Central Department of Environmental Science, Tribhuvan University
Preshika Baskota
Research Asst., Central Department of Environmental Science, Tribhuvan University
Glacial Hazards and Avalanches in High Mountains of Nepal Himalaya
Journal of Tourism and
Himalayan Adventures
An International Research Journal
June 2020, Vol. 2, ISSN : 2717-5030 (Print) 2738-9642 (Online)
Nepal Mountain Academy
Thakuri, Chauhan, Baskota | 88
snow and ice and supply water downstream during the dry periods, but the traveler and
mountain dwellers are usually unsafe and insecure due to various mountain hazards.
Mountains present varieties of hazards (Table 1), including glacial hazards. Unlike low lying
plain areas, various mountain hazards can be observed in the Nepal Himalaya. The possible
mountain hazards are (a) swollen river/increased discharge/river ow – high water levels, (b)
avalanches, (c) serac collapse, (d) landslides – downslope movement, (e) debris ow, (f) rock
falls, (g) crevasses, (h) extreme weather/storm, (i) high altitude sickness (Acute mountain
sickness, High-altitude pulmonary Oedema, High-altitude cerebral oedema); and (j) snow
cornices (Corona & Stoffel, 2016; Gruber & Haeberli, 2007; Zingari & Fiebiger, 2002;
Richardson & Reynolds, 2000).
The GHs are the processes related to mountain glaciers, ice caps, or ice sheets that threaten
lives and properties. High mountains are particularly prone to GHs related to snow, ice and
permafrost as these elements exert key controls on mountain slope stability. Two main types
of GHs can be observed in high mountains: (1) direct action of ice and/ or snow; this includes
events such as avalanches of ice, and snow, glacier outburst oods and glacier advances, and
permafrost hazards, and (2) indirect GHs that arise as a secondary consequence of a glacial
feature or process and may include catastrophic breaching of moraine dammed lakes, rock
avalanche etc. (Hewitt, 2002 & 2009; Richardson & Reynolds, 2000; Bell et al., 1990). The
GHs have a direct connection and consequences for human society as they can impact on
infrastructure, hydropower, agriculture, and tourism through the loss of lives and properties.
Further, these hazards are the potential threats for the mountaineering activities that can
destroy the infrastructures, trekking trails, and result in the demise of mountain climbers
(Thakuri & Koirala, 2019; McClung, 2016; Mu & Nepal, 2016).
Table 1: Loss of lives in the country by disasters in the last decade (2011-2019) (MoHA,
Types of Hazards 2011 2012 2013 2014 2015 2016 2017 2018 2019
Avalanche 9 8 16 23 1 8
Cold Wave 41 25 2 1 47
Earthquake 6 1 0 8962
Epidemic 9 33 4 12 3 19 10 5
Fire 25 77 59 67 75 63 63 87 77
Flood 126 52 131 129 0 101 166 17 73
Landslide 110 60 87 113 138 148 70 91 86
Storm (Snow, Wind,
6 18 3 43 12 2 5 24 42
Thunderbolt 76 118 147 97 103 118 85 75 94
Total 399 393 441 477 9316 451 401 346 380
In this paper, we present different glacial hazards with focus on the avalanches (snow, ice,
and rock), We also share the relevant policies in the GHs and lays groundwork for future
research on the high-altitude hazards. The paper is based on the analysis of the existing data
and published literatures. Data on avalanche hazards were collected from different sources,
graphically presented, and documented. Literatures were searched by using some key words,
like “glacial hazards”, “avalanche”, “disaster”, “glaciers”, and high-altitude. In this study,
literatures published (journal articles, conference proceedings, abstracts, thesis, project
reports) up to the end of February 2020 are incorporated.
Journal of Tourism and Himalayan Adventures, Vol. 2 ISSN: 2717-5030 (Print) 2738-9642 (Online)
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Glacial hazards
Avalanche hazards
As the peaks of northern part of the country are covered with ice/snow, avalanches are very
common in Nepal and claim the life of human and loss of properties (McClung, 2016). An
avalanche is a massive slide of snow, ice, rock or debris down a mountainside, caused by the
released build-up of snow (Park & Reisinger, 2010) and thus, can appear as a) snow, b) rock,
c) ice avalanches, or d) mix of any of these. It is typically caused when material on a slope
breaks loose from its surroundings which then quickly collects and carries additional material
down the slope. Various kinds of avalanches exist in the mountains, including rock avalanches
(which consist of large segments of shattered rock; Deline et al., 2015; Hewitt, 2002 & 2009),
ice avalanches (which typically occur in the vicinity of a glacier), and debris avalanches
(which contain a variety of unconsolidated materials, such as loose stones and soil) (Birkeland,
2018). Avalanche usually occurs when stress from the pull of gravity and/or applied load
exceeds the strength of the snow cover. Although avalanches can occur on any slope given
the right conditions, certain times of the year and certain locations are naturally more
dangerous than others. Wintertime, particularly from December to April, is when most
avalanches tend to happen (NSIDC, 2019). About 90% of all avalanches begin on slopes of
30-45°, and about 98% occur on slopes of 25-50°. Avalanches strike most often on slopes
above timberline that face away from prevailing winds (leeward slopes tend to collect snow
blowing from the windward sides of ridges).
Landslides and snow avalanches cause major disasters on a global scale every year, and the
frequency of their occurrence seems to be on the rise (Nadim et al., 2006). The main reasons
for the observed increase in landslide disasters are a greater susceptibility of surface soil to
instability and greater vulnerability of the exposed population. Furthermore, traditionally
uninhabited areas such as mountains are increasingly used for recreational and transportation
purposes, pushing the borders further into hazardous terrain (Nadim et al., 2006). Snow
avalanches represent a signicant natural hazard to infrastructure and residents in high
mountain regions of the world (Brundl et al., 2004; cited in Laxton & Smith, 2009). Tourism
destinations are easily impacted by a variety of natural disasters which cause serious damage
to the visited regions (Murphy & Bayley, 1989; cited in Park & Reisinger, 2010). The
occurrence of natural disasters leads to a decrease in the tourists’ arrivals (Park & Reisinger,
GLOF hazards
ICIMOD (2011) reported 24 glacial lake outburst ood (GLOFs) in Nepal. Further, some
other GLOFs events (e.g., Figure 1) have been reported until 2018 from different parts of
Nepal (Thakuri & Koirala, 2019). About 28 GLOF events have already been experienced in
the Nepal Himalaya causing the loss of lives and properties, originating from the outburst of
lakes located in Nepal and the Tibetan part of China.
Many glacial lakes are emerging as potentially dangerous once due to enlargement from the
combination of small lakes and melting of the glacier ice (Khadka et al., 2018; Salerno et al.,
2016). Even the Tsho Rolpa Glacial Lake located in the eastern Nepal (Figure 2), which was
lowered by 3 m water level in 2000 for preventing from the outburst (Rana et al., 2000), is
recently emerging as the most dangerous lake threatening downstream population. The lake
was 149 hectares in 2000 just after the lake lowering activity, while in 2018; the lake surface
area has increased to 160 hectares (increased by about +7%). This lake is prone to frontal
Thakuri, Chauhan, Baskota | 90
Figure 1: Comparison of satellite imagery before (a) and after (b) the glacial lake outburst ood of the Langmale
Glacial Lake in the Barun valley of the eastern Nepal. A focused outwash plain with sediment deposits from the April
20, 2017 GLOFs (Byer et al., 2018) is shown in (c) (Source: GoogleEarth, 2020).
Figure2: (a) Tsho Rolpa Glacial Lake, b) Comparison of lower part of the lake, showing that the lake elevation has
increased in recent year. Small permanent islands in the middle of the lake are submerged under the water, and c)
The lake is expanding toward the northeast by melting the glacier ice (Source: GoogleEarth, 2020).
moraine dam break. This glacial lake is connected to the glacier ice on one side (eastward).
The lake can increase in the size (towards – southeast) further more by melting the glacier
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Figure 3: Avalanches recorded in Nepal Himalaya from 1922 to 2020: Showing avalanche prone areas based on the
previous avalanche records (Table 2). The Everest region is the most disastrous place for avalanches.
Permafrost hazards
The permafrost is a ground (soil or rock, and included ice and organic material) that remains
at or below 0 °C for at least two consecutive years (Van Everdingen, 1998). It is, therefore,
called as a permanently frozen ground and is dened exclusively on the basis of temperature
irrespective of texture, degree of induration, water content or lithological characteristics.
Since permafrost is a thermal state, the determination of the energy balance to the ground is
very important for its modelling and prediction of future changes (Chauhan & Thakuri, 2017;
Arenson, 2002). Several factors and effects have a major inuence on the thermal regime in
the ground. Perennially frozen ground is very sensitive to climate change. Due to the retarded
response of permafrost to cycles of air temperature, permafrost temperatures have been used
to examine past climate changes. Climate change may result in new different ground freezing
conditions, thereby inuencing the surface velocity and the maximum depth of soliuction
processes (Gruber & Haeberli, 2007).
Permafrost hazards relate to infrastructure that is partly or entirely placed in the vicinity or on
top of the permafrost- and glacier-affected frozen rock masses or debris. Changes in
permafrost and glacier dynamics may derive from atmospheric warming, but as well from
human-environment interaction (Gruber & Haeberli, 2007). Mountain infrastructure can be
negatively affected by ground-ice degradation induced by the combined effects of construction
activity, the structure itself and climate change (Bommer et al., 2010). A widespread loss of
permafrost will trigger erosion or subsidence of ice-rich landscapes and in addition, the
thawing will have a severe impact on infrastructure due to excessive settlements and
exploration, and will result in rapid coastal erosion (Arenson, 2002).
Snow, ice and rock avalanche: Splendid mountains turn into dangerous
More than 60 avalanches tolling 372 persons death since 1922 has been reported from the
Thakuri, Chauhan, Baskota | 92
Figure 5: Tragedy in the Himalaya: An ice-snow avalanche originating from the steep slope of Mt Everest hit the
Khumbu ice fall and Everest base camp in 2014 (Source: B.B Rai/AFP/Getty Images).
Nepal Himalaya (Figure 3 & Table 2). Almost all the high-altitude regions of Nepal are prone
to avalanches (Figure 3). The avalanche records since 1922 show that the number of casualties
and the avalanche events are the highest in the Khumbu region compared to other parts of
Nepal (Figure 3 & 4). In recent years, the records and the casualties are expanding in other
parts of the country which might be due to increased human (tourism) activities and the
recording system.
Figure4: A historic timeline of the major avalanche events in Nepal Himalaya from 1920 to 2020, developed based
on dierent data sources (For further details, referred to Table 2)
The 18 April 2014 avalanche was the second deadliest disaster in the history of Mt. Everest
(8848 m) in Nepal, after the avalanches that struck the southern side of the mountain following
year on 25 April, 2015, which were triggered by an earthquake of magnitude 7.8 in Nepal
Figure 5; McClung, 2016). An avalanche occurred in the early morning towards the southern
side of Mt. Everest at an elevation of approximately 5800 m, near Everest Base Camp (ABC).
Within the Khumbu Icefall, on the route between camp I and camp II, this was the disastrous
avalanche that killed 16 men, mostly the Sherpa guides.
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On 25 April 2015, a series of avalanches triggered by the earthquake of magnitude 7.8 in
Nepal. Climbers at the base camp of the Mt Everest and others on the higher elevations were
trapped during the disaster (McClung, 2016). At least 23 people were killed and 61 injured.
The avalanche began in the late morning on Mount Pumori (7,161 m), a mountain just a few
kilometers west of the Everest, gathering strength as it headed toward the base camp, where
climbing expeditions were preparing to make their way to the summit. Furthermore, the
earthquake triggered avalanches, landslide, and rock falls in the Langtang valley which
caused the loss of more than 350 people's lives and destroyed the village of Langtang (Fujita
et al., 2017; Kargel et al., 2016). These casualties are categorized under the Earthquake
hazards since it was difcult to discern the direct cause of the avalanches (Table 1) and
excluded in Figure 3 and 4.
On 14 October 2014 a snowstorm and series of avalanches occurred on and around Annapurna
and Dhaulagiri in the Manang and Mustang Districts of Nepal. Injuries and fatalities resulted
in the deaths of at least 43 people of various nationalities, including at least 21 trekkers. The
storm arose from the Cyclone Hudhud (NDMA, 2015) and was the worst in a decade with
almost 1.8 m of snowfall within 12 hours.
Figure 6: Steep mountain slopes are the potential source of the rock/ice avalanche. (Source: S. Thakuri, 2014)
Thakuri, Chauhan, Baskota | 94
Table 2: Avalanches occurred in the Nepal Himalaya and human casualties due to avalanche
and snowstorm for the year 1922 to February 2020. The years 1995, 2014, and 2015 are the
top three years with more deaths due to avalanche and snowstorms. The data is compiled
from different literatures.
Year Incident Incident description Total death
1922 Avalanche British Mount Everest Expedition 7
1952 Avalanche Swiss expedition, Lhotse Face 1
1970 Avalanche Ice-fall avalanche in the Khumbu Icefall, during
production of “The Man Who Skied Down
Everest” between Base Camp and Camp I
1972 Avalanche/Snowstorm South Korean Mountaineering Expedition,
Nepalease Sherpa, Koreans and Japanese killed
at the 26,658 feet of Mt. Manaslu
1973 Avalanche/Snowstorm S.W. Face 9
1974 Avalanche French expedition from the West Ridge to Mt.
1977 Avalanche Sisne Himal 1
1978 Avalanche/Snowstorm Khumbu Icefall 7
1979 Avalanche/Snowstorm Below North Col, Japanese Alpine Club
reconnaissance expedition
1980 Avalanche/Snowstorm 7900 m North Face 10
1981 Avalanche/Snowstorm 6900 m W. Cwm 4
1982 Avalanche/Snowstorm Khumbu Icefall 7
1984 Avalanche Ice-fall avalanche in the Khumbu Icefall 3
1987 Avalanche/Snowstorm Everest basecamp 2
1988 Avalanche Climbers’ camp at 23,625 feet towards Mt.
1989 Avalanche/Snowstorm Polish Climbers on Mt. Everest on a 7200 m W.
and Spanish climbers in Mt. Pumori while
traversing Mt Pumori’s exposed slopes
1990 Avalanche/Snowstorm Everest region 6
1991 Avalanche/Snowstorm Everest region 8
1992 Avalanche/Snowstorm Khumbu region 2
1994 Avalanche/Snowstorm Everest region 2
1995 Avalanche/Snowstorm Intense snowfall generated numerous avalanches
throughout the Khumbu region
Near Mt. Kanchenjunga base camp
1996 Avalanche/Snowstorm Mount Everest during attempts to descend from
the summit, at Lhotse face
1997 Avalanche/Snowstorm Everest region, Everest 19
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1998 Avalanche/Snowstorm Everest region, Everest 6
1999 Avalanche/Snowstorm Everest region, Everest; Chunchet, Gorkha 6
2005 Avalanche/Snowstorm Powder-snow avalanche, induced by several
hours of heavy snowfall, plowed into a French
expedition’s base camp
2006 Avalanche Due to a massive serac (ice fall) collapsing at the
Khumbu icefall on Mt Everest
2007 Avalanche/Snowstorm Everest region, Everest 6
2009 Avalanche Khumbu Icefall 2
2010 Avalanche Big avalanche swept away a leading Sherpa
along with his guide, in windy conditions xing
ropes near the summit of Mount Baruntse
2012 Avalanche Avalanche hit camp three of the Manaslu peak,
resulting in a ood of snow
2013 Avalanche Everest region, Everest 8
2014 Avalanche/Snowstorm Snowstorm and series of avalanches occurred on
and around Annapurna and Dhaulagiri in the
Manang and Mustang districts;
Seracs on the western spur of Mount Everest
failed, resulting in an ice avalanche
2015 Avalanche/Snowstorm Shaking from the 25 April 2015 earthquake
triggered an avalanche from Pumori into Base
Camp on Mount Everest
2017 Avalanche 11-year-old boy went missing in an avalanche at
Chorkhola area in Kaike village council, Dolpa
while they were going to their animal sheds in
Chormara Lek
2018 Avalanche/Snowstorm Heavy snowstorm followed by landslide buried
the base camp of Mt. Gurja at 3,500 m on the lap
of the south face of Mt Dhaulagiri
2019 Avalanche Avalanche at Annapurna trekking route in
Nesyang Rural Municipality of Manang district;
Dolpa; Dhading
Avalanche Avalanche struck the famous Mount Annapurna
circuit climbing route (3230 m) after heavy rains
and snow
Storms and avalanches of Khumbu and Kanchenjunga Himal (1995)
On November 9 and 10, 1995, a severe storm hit the Nepal Himalaya, triggering several
snow and ice avalanches in different parts of the country. As a result, 24 people were killed
in a lodge near the village of Pangkha in the Gokyo Valley (Yamada et al., 1996) and 7 other
deaths resulted from an avalanche in the Kanchenjunga area of far eastern Nepal (Kattelmann
& Yamada, 1995). This storm was the most intense event to occur during the autumn in the
recorded past at least 50 years. The autumn season in the Himalaya tends to be quite dry, so
this storm seemed extraordinary. Precipitation gauges at lower elevations caught 50 to 200
Thakuri, Chauhan, Baskota | 96
mm of rain during the storm. Cold temperatures led to snowfall above 3,500 m in the Khumbu
region, and snow depths increased rapidly with elevation. About 30-50 cm of snow fell at
3,800 m; 50-100 cm of snow was found at about 4,000 m; and 100-200 cm of snow was
deposited above 5,000 m. The intense snowfall generated numerous avalanches throughout
the region.
The aforementioned three events are the largest reported storms and avalanches events in
Nepal. The events not only hampered the tourism industry of Nepal, but also directly affected
the life of the people who were employed only because of tourism.
Triggers and avalanche risks in high mountains
Triggering factors
Avalanches are triggered by either natural forces (e.g., precipitation, wind drifting snow,
rapid temperature changes) or human activities. Overloading of snow on the slope, shearing
and bonding of snow molecules, vibrations resulting from sound, skiing, earthquake,
construction, and explosive blasts etc. trigger the avalanches. According to Schweizer (2003),
the triggering of an avalanche can occur as a result of (i) localized rapid near-surface loading
by, for example, people or explosives (the latter being called articial triggering), (ii) gradual
uniform loading due to precipitation or other factors, or (iii) a no-loading situation that
changes snowpack properties, for example, surface warming (called natural triggering or
spontaneous release).
Figure 7: Heavy precipitation (up to 150 mm rain to hit central Nepal; 150 mm rain is nearly equivalent to 3000 mm
snow) was predicted in Nepal during the tropical Cyclone Hudhud, begun to form on 6 October 2014 and dissipated
on 14 October 2014 (NDMA, 2015) triggered heavy snowstorm in the Annapurna region, killing at least 43 persons
Complex interactions between the terrain, snowpack, and meteorological conditions lead to
avalanche process. The only constant factors for the snow avalanche are the terrain
characteristics and slope with an inclination greater than 30° (Corona & Stoffel, 2016).
Terrain roughness also inuences avalanche formation by hindering the formation of
continuous, weak snowpack layers (Schweizer, 2003). The day to day stability of snowpack
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is also inuenced by the orientation of the slopes with respect to the sun and dominant winds.
Most of the factors contributing to snow avalanching are related either to the strength or to
the load of snow and its variation over time. In addition to terrain, four essential factors
leading to the release of snow avalanches are precipitation (snowfall), wind, temperature, and
snowpack stratigraphy (Corona & Stoffel, 2016; Schweizer, 2003). Being the phenomena
controlled by climate, snow and ice avalanches are not only expected to be affected by
changes in atmospheric conditions, but also by climatic change.
A rock avalanche, sometimes referred to as sturzstrom, is a type of large and fast-moving
landslide (Deline et al., 2015). Occurrences of rock avalanches are affected by several factors
such as (i) inherent factors (e.g., rock structure, slope form), (ii) preparatory factors (e.g.,
weathering, climate change), (iii) triggering factors (e.g., earthquake, rainstorm) (Weidinger
et al., 2002), and (iv) factors that may affect mobility (e.g., glacier surface) (Pacione, 1999).
Permafrost thaw could also trigger the rock avalanche as the freeze-thaw action is condition
by the temperature uctuations and volumetric expansion of ice on the slope generally widens
existing fractures and prepares for rock failure (Gruber & Haeberli, 2007). Climate change
and more extreme weather conditions may also be contributing factors. Earthquakes often
trigger avalanches, rock falls and tsunamis (Fujita et al., 2016; Park & Reisinger, 2010).
Observations indicate that most natural avalanches are triggered by heavy snowfall (Conway
& Wilbour, 1999; Hirashima et al., 2008), a sharp rise in temperature or rainfall (Baggi &
Schweizer, 2009; Gauthier et al., 2017) as well as earthquakes (Podolskiy et al., 2010; Pérez-
Guillén, et al., 2014; cited in Hao et al., 2018). The 2015 earthquake triggered avalanches in
the Mount Everest region and in the Langtang Valley attened the villages and people were
made homeless within less than a minute (Kunwar & Limbu, 2015).
Avalanche risks
Snow, ice, and rock avalanches have frequently been responsible for large disasters in high
mountains. Different evidences of avalanche can be observed based on the altitudinal gradient
(Zimmermann et al., 1986). Above the snowline, the avalanches occur throughout the year,
but especially during and after the summer monsoon. At this region, avalanche can be
observed directly. Below the snowline, avalanche occurrences are very rare. Rock avalanche
can be observed occasionally at these elevations (Deline et al., 2015).
Nepal is considered as one of the most susceptible countries for the climate risk, according to
the Global Climate Risk Index (GCRI), which assesses the impacts of meteorological events
in relation to economic losses and human fatalities (Eckstein et al., 2019). The country is in
top 20 of all the multi-hazard countries in the world. More than 80% of the population is
exposed to the risk of natural hazards (MoHA, 2017), which include water-induced disasters
and hydro-meteorological extreme events such as droughts, storms, oods and inundation,
landslides, debris ow, soil erosion, avalanches, extreme temperature, and glacier lake
outburst oods (GLOFs). The existing mechanisms for developing risk assessments in Nepal
are presented in Table 3.
The frequency of avalanches may increase due to the global warming. Nepal Himalaya is
experiencing a continuous elevation-dependent warming in the last four decades, i.e., high
mountains areas are more rapidly warming compared to the southern lowlands. Maximum air
temperature has increased by 0.045 °C/yr and the minimum temperature by 0.009 °C/yr from
1976 to 2015 (Thakuri et al., 2019). Glacial lakes are considered a sensitive indicator of
climate change and glacier dynamics (Salerno et al., 2016). In the situation of outburst,
Thakuri, Chauhan, Baskota | 98
glacial lakes can threaten the downstream communities and have signicant socio-ecological
consequences. The glacial lakes, mostly located above 4000 m elevation, show heterogeneous
rates of expansion in different river basins and by elevation zones, with apparent decadal
emergences and disappearances in the Nepal Himalaya. In general, both the number and
surface areas of the glacial lakes has increased continuously in the last four decades. Overall,
the glacial lakes exhibited ~25% expansion of the surface areas in the last three decades
(Khadka et al., 2018). A continued expansion of the glacial lakes is posing the risk of GLOFs
threatening the downstream population and infrastructure.
Table 3: Existing mechanisms for developing risk assessments in Nepal
(Adopted from UNDRR, 2019)
Assessment Mechanism Method
Nepal Hazard Risk Assessment
(NHRA) 2010
Multi-hazard risk map for Nepal, based on description of the
available data, hazard assessment and mapping for earthquakes,
oods, droughts, landslides and epidemics at the national level.
Urban Risk Atlas (URA) 2013 The URA was developed based on RADIUS tool for risk analysis.
The data input includes base maps, major infrastructure, buildings,
critical infrastructure, building typologies and number of people at
home when the earthquake occurs as basic for casualty estimations
(based on day/night cycle).
Vulnerability and Risk
Assessment Framework
(VRAF) 2017
VRAF describes a conceptual framework for vulnerability and risk
assessment, methodological process for conducting VRAF and
provides a set of vulnerable and risk indicators to be accounted for
in different sectors, i.e. urban settlement & infrastructure, water
resources & energy. This supports the measurement of climate risk
to determine climate adaptation priorities and devising climate
adaptation strategies.
Policies and legal provisions
The Constitution of Nepal (2015) has identied disaster management as one of the key
priorities of all tiers of the government (federal, provincial and local) in the list of the
concurrent powers of the federal, provincial and local levels. To meet the vision of the
Constitution, a comprehensive Disaster Risk Reduction and Management (DRRM) Act
(2017) was endorsed by the Nepal government. Later in 2018, the National Policy on Disaster
Risk Reduction 2018 and the National Disaster Risk Reduction Strategic Action Plan (2018-
2030) were endorsed, to further strengthen the government’s initiatives on DRM (MoHA,
2019; Table 4).
The DRRM Act (2017) focuses on the disaster risk reduction as well as management. The act
was developed in the federal context of Nepal and makes provision for the formation of
National Disaster Management Council, National Disaster Risk Management Authority,
Disaster Management Committees at all three tiers of the government and executive
committees at federal and provincial levels. Although this act and its regulations have not
focused on the hazard specic disaster, it includes both natural and non-natural disaster. It
denes ‘natural disaster’ as the disaster that is caused due to snowfall, hailstorm, avalanche,
GLOF, heavy rainfall, drought, ood, landslide and soil erosion, inundation, storm, cold
waves, heat waves, lightening, earthquake, volcano, wild res and other types of hazards.
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Therefore, the act is inclusive of the GHs. Similarly, the act makes provision for declaring
any area that has been hit by serious natural disaster as the ‘Disaster Crisis Zone’. This
provision is particularly relevant in the context of high mountain areas which are often hit by
large, but unprecedented disasters such as landslides, avalanches and GLOFs.
The National Disaster Risk Reduction Policy (2018) mainly aims at reducing signicantly
the loss and damage of life and property, human health, livelihood and productive resources,
physical and social infrastructures, cultural and environmental heritage from natural and
human-caused hazards. The policy is aligned with the priority areas of the Sendai Framework
for Disaster Risk Reduction (SFDRR). Among 59 SFDRR polices adopted, some of them are
directly related in managing high mountain disaster while others are linked indirectly. The
policy has put emphasis on providing disaster management information to the general public
and stakeholders by developing disaster management information based on Remote Sensing
System, Geographic Information System and Open source Technology. It encourages
research on disaster risk, mitigation, preparedness, and capacity building on search and
rescue, reconstruction and recovery and therefore envisions establishing National Disaster
Risk Reduction Research and Training Academy. Although the word ‘avalanche’ has not
been mentioned anywhere in the policy document, it aims to continuously monitor glacial
lakes and other mountain hazards, and develop and implement forecast-based preparedness
and response plan. Much emphasis has been given to the development and implementation of
well-functioning early warning system, which is the necessity of high mountain hazards such
as heavy snowfall, storms, glacial lake outbursts, and avalanches. The policy encourages the
development and use of Web-based systems, Mobile Apps, Short Message Service, Interactive
Voice Response, Emergency Telecommunication for the communication of early warning
information for effective and timely preparedness and response.
Table 4: Nepal’s legislative frameworks for disaster risk reduction (Adopted from UNDRR,
Legislation Purpose Scope Responsible
Natural Calamity
Relief) Act, 1982
(Amended in 1989;
First structured disaster policy of
Nepal; Legal instrument focusing on
disaster response. The Act gave
MoHA the responsibility to oversee
overall disaster management activities.
districts and
Ministry of
Home Affair
Local Self Governance
Act 1999
Delegated administrative power to
local authorities on overall local
development processes including
disaster risk reduction.
Municipalities Local
National Action Plan
for Disaster Risk
Management 1996
Action plans for pre-disaster and
post-disaster phase.
districts and
Ministry of
Home Affairs
National Strategy for
Disaster Risk
(NSDRM) 2009
Formulated to set up 29 strategies to
transform Nepal’s response- focused
disaster management approach to a
more comprehensive and proactive
risk reduction approach.
National Ministry of
Home Affairs
Thakuri, Chauhan, Baskota | 100
Nepal’s New
Constitution 2015
Mentions DRM for the rst time under
Article 51 and has clearly assigned
DRM as a concurrent responsibility
for all tiers of government.
districts and
Government of
Disaster Risk
Reduction and
Management Act
Replaces the Natural Calamity (Relief)
Act 1982. Sees disaster risk
management as a process focusing on
different stages of the disaster
management cycle.
National Ministry of
Home Affairs
Local Government
Operation Act, 2017
Outlines the roles and responsibilities
of Urban and Rural Municipalities.
Districts and
Ministry of
Home Affairs
National Disaster Risk
Reduction Policy 2018
(Nation DRR Policy
Serves as the national framework for
disaster risk reduction, aligned with
the SFDRR, with the vision:
Sustainable Development through
DRR actions and climate change
National Ministry of
Home Affairs
National Disaster Risk
Reduction Strategic
Action Plan, 2018 -
2030 (NDRRSAP)
Guides priorities of actions towards
the concluding years of SFDRR.
National Ministry of
Home Affairs
The National Disaster Risk Reduction Strategic Action Plan (2018-2030) (NDRRSAP) was
formulated based on the learnings and challenges of implementing a National Strategy for
Disaster Risk Management (2009) to fulll the commitments made by Nepal as part of the
Sendai Framework for Disaster Risk Reduction (2015-2030). The NDRRSAP has identied
4 priority areas and 18 priority actions to be carried out in the short term (by 2020), medium
term (by 2025) and long-term (by 2030) basis for disaster risk reduction and management in
Nepal. The four priority areas are (i) understanding the disaster risk, (ii) improving disaster
risk governance at federal, provincial and local level, (iii) promoting private and public
investment for enhancing disaster risk reduction and resilience based on multi-hazard risk
knowledge and (iv) improving preparedness for effective response and recovery and build
back better. Under the rst priority area, NDRRSAP adopts following strategic activities to
understand the underlying risk of high mountain hazards such as avalanche and glacial lake
outburst ood:
Establish a real time snow, glacier, and glacial lake observation system;
Prediction, mapping and scoping of major glacier, avalanche, GLOF affected areas
and making that information publicly available;
Map out the infrastructures, settlement and population (disaggregated) at risk of
glacier, avalanche, GLOF in terms of exposure and vulnerability and disseminate the
information for public use;
Prepare glacier, avalanche, GLOF risk sensitive land use plan and make it publicly
Under other priority areas, the NDRRSAP has emphasized on promoting preparedness, multi
hazard early warning system, community-based disaster risk reduction, risk transfer, and
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Glacial... | 101
capacity building in search and rescue.
The Local Government Operation Act (2017) has also mandated local governments to take
initiatives on DRRM to mainstream in the development, risk reduction and natural resource
management. Similarly, the Climate Change Policy of Nepal (2019) aims to reduce the loss
of climate-induced disasters to lives and property, health, livelihoods, physical infrastructures
and cultural and environmental resources. It aims to enhance and make preparedness and
response effective by developing, monitoring, forecasting, and early warning system for
disasters including ood, landslide, land erosion, avalanche, drought, lightning, windstorm,
heat wave, cold wave, wildre, re etc.
The Sendai Framework for Disaster Risk Reduction (2015-2030) is the major international
commitments on disaster risk reduction that Nepal has made for managing disaster risk. This
was adopted by UN Member States on 18 March 2015 at the Third UN World Conference on
Disaster Risk Reduction in Sendai City, Miyagi Prefecture, Japan. The Sendai Framework is
the rst major agreement of the post-2015 development agenda, with seven targets and four
priorities for action. The Framework aims to achieve the substantial reduction of disaster risk
and losses in lives, livelihoods and health and in the economic, physical, social, cultural and
environmental assets of persons, businesses, communities and countries over the next 15
Concluding remark
GHs are issues of glacier, snow and ice-covered areas (referred as “cryosphere”) in the
northern part of Nepal. The avalanches are triggered by the human activities, earthquake,
heavy precipitation and wind and aggravated by the climate change. Climate change can
increase the intensity of the hazards, including the increased number of avalanches, rock falls
and landslides in the mountain slopes. Due to resource limitations and difcult working
environment, limited information is available on the avalanches in the high mountains of
Nepal. Yet the risks from these events are growing in many of mountain areas, due to
increased populations, infrastructural developments, utility facilities, and even increasing
human activities. There are many policies and legislation that are developed for disaster risk
reduction and management. Most of them are focused on multi-hazard risk rather than
focusing on a single hazard. The existing provisions regarding the high mountain disaster
management are focused on understanding the underlying risk of the mountain hazards,
developing effective early warning system, and effective warning communication mechanism,
capacity building for search and rescue and enhancing the role of local governments for
disaster management.
No legislative provision exists for addressing the hazard specic disasters, e.g., avalanche
and the high-altitude GHs in the country, but instead exists overarching act and its regulations
for both natural and non-natural disaster in the country. A separate policy for addressing the
mountain hazards such as avalanche, ashood and GLOF is required. At the same time,
emergency response plan and operating procedure for search and rescue is of immediate need
for the large mountain disaster such as the Khumbu avalanche. The visitors and mountaineers
visiting in the high mountains need reliable information about the mountain geo-hazards and
their associated risks. Satellite-based hazard assessment is an effective technique for certain
hazards, e.g., GLOFs, rock fall etc., however eld-based in-situ measurements are necessary
in most cases. Hazard maps, monitoring of the rock fall events, permafrost conditions, and
early information to the mountaineers can aid to make accurate and timely decision.
Thakuri, Chauhan, Baskota | 102
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... This trend was similar to the meteorological observations at a nearby Tingri Station [11]. Although both temperature and humidity will affect evapotranspiration of the lake, the increase in temperature and precipitation has elevated freezing levels in the post-monsoon and early winter periods [58] and may boost the water supply of glacial lakes due to increased glacier ablation and runoff, which cause a negative effect on evapotranspiration [59], and eventually cause the lake level to rise (for example Lake Tsho Rolpa [60]) or induce a GLOF (please see Lake A in Section 5.4). ...
... This avoids some small-scale GLOFs but increases the effect when large-scale GLOFs occur. For example, a recent study [60] has shown that the Tsho Rolpa lake elevation has increased in recent years. If the lake area gradually increases, as we expect (see Section 5.3), the water pressure on the dam body will be greatly increased. ...
Full-text available
Climate warming and concomitant glacier recession in the High Mountain Asia (HMA) have led to widespread development and expansion of glacial lakes, which reserved the freshwater resource, but also may increase risks of glacial lake outburst floods (GLOFs) or debris floods. Using 46 moderate- and high-resolution satellite images, including declassified Keyhole and Landsat missions between 1964 and 2020, we provide a comprehensive area mapping of glaciers and glacial lakes in the Tama Koshi (Rongxer) basin, a highly glacierized China-Nepal transnational catchment in the central Himalayas with high potential risks of glacier-related hazards. Results show that the 329.2 ± 1.9 km2 total area of 271 glaciers in the region has decreased by 26.2 ± 3.2 km2 in the past 56 years. During 2000–2016, remarkable ice mass loss caused the mean glacier surface elevation to decrease with a rate of −0.63 m a−1, and the mean glacier surface velocity slowed by ~25% between 1999 and 2015. The total area of glacial lakes increased by 9.2 ± 0.4 km2 (~180%) from 5.1 ± 0.1 km2 in 1964 to 14.4 ± 0.3 km2 in 2020, while ice-contacted proglacial lakes have a much higher expansion rate (~204%). Large-scale glacial lakes are developed preferentially and experienced rapid expansion on the east side of the basin, suggesting that in addition to climate warming, the glacial geomorphological characters (aspect and slope) are also key controlling factors of the lake growing process. We hypothesize that lake expansion will continue in some cases until critical local topography (i.e., steepening icefall) is reached, but the lake number may not necessarily increase. Further monitoring should be focused on eight rapidly expanding proglacial lakes due to their high potential risks of failure and relatively high lake volumes.
... Some publications report that Nepal's Himalayan region is at high risk from climate change (Government of Nepal 2010; ICIMOD 2011; Thakuri et al. 2020). Climate change is disrupting the socio-ecological systems from its past state. ...
Full-text available
Periglacial environment in the Nepal Himalaya (80°04’ to 88°12’ E longitude and 26°22’ to 30°27’ N latitude) is a research field that has received a little scientific attention although the first reported periglacial research was in 1958. After the first periglacial research, only 22 studies are reported in Nepal (area: 147,181 km2), most of which is carried out by researchers outside the country. Studies mainly focus on periglacial landforms and determining the lower limit of the mountain permafrost. The mean lower limit of permafrost (LLP) and the size of rock glaciers indicate a decreasing trend of the permafrost limit from the eastern (5239 m a.s.l.) to the western part of Nepal (4513 m a.s.l.). The rate of change in the LLP in response to climate change in Nepal Himalaya is 1.3–2.6 m/yr. Model on the scenario of permafrost change based on the IPCC climate scenarios shows that the LLP would rise by 188 m between 2009 and 2039 with the rise in temperature. The periglacial landforms, like vegetated patterned ground (earth hummocks, turf banked terraces), sorted polygons, sorted stripes, solifluction lobes, striated ground, and rock glaciers are reported from the Nepal Himalaya. The spatial and temporal coverage of periglacial research in Nepal Himalaya is very low. The arena of periglacial researches, like permafrost distribution modelling, periglacial hazards, periglacial ecology, relationships between permafrost and rangeland, and implication on mountain livelihood, global warming and periglacial change are the potential areas of research in the coming days.
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Himalayan glaciers, in general, are shrinking and glacial lakes are evolving and growing rapidly in number and size as a result of climate change. This study presents the latest remote sensing-based inventory (2017) of glacial lakes (size ≥0.0036 km2) across the Nepal Himalaya using optical satellite data. Furthermore, this study traces the decadal glacial lake dynamics from 1977 to 2017 in the Nepal Himalaya. The decadal mapping of glacial lakes (both glacial-fed and nonglacial-fed) across the Nepal Himalaya reveals an increase in the number and area of lakes from 1977 to 2017, with 606 (55.53 ± 16.52 km2), 1137 (64.56 ± 11.64 km2), 1228 (68.87 ± 12.18 km2), 1489 (74.2 ± 14.22 km2), and 1541 (80.95 ± 15.25 km2) glacial lakes being mapped in 1977, 1987, 1997, 2007, and 2017, respectively. Glacial lakes show heterogeneous rates of expansion in different river basins and elevation zones of Nepal, with apparent decadal emergences and disappearances. Overall, the glacial lakes exhibited ~25% expansion of surface areas from 1987 to 2017. For the period from 1987 to 2017, proglacial lakes with ice contact, among others, exhibited the highest incremental changes in terms of number (181%) and surface area (82%). The continuous amplified mass loss of glaciers, as reported in Central Himalaya, is expected to accompany glacial lake expansion in the future, increasing the risk of glacial lake outburst floods (GLOFs). We emphasize that the rapidly increasing glacial lakes in the Nepal Himalaya can pose potential GLOF threats to downstream population and infrastructure.
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On April 20, 2017, a flood from the Barun River, Makalu-Barun National Park, eastern Nepal formed a 2–3-km-long lake at its confluence with the Arun River as a result of blockage by debris. Although the lake drained spontaneously the next day, it caused nationwide concern and triggered emergency responses. We identified the primary flood trigger as a massive rockfall from the northwest face of Saldim Peak (6388 m) which fell approximately 570 m down to the unnamed glacier above Langmale glacial lake, causing a massive dust cloud and hurricane-force winds. The impact also precipitated an avalanche, carrying blocks of rock and ice up to 5 m in diameter that plummeted a further 630 m down into Langmale glacial lake, triggering a glacial lake outburst flood (GLOF). The flood carved steep canyons, scoured the river’s riparian zone free of vegetation, and deposited sediment, debris, and boulders throughout much of the river channel from the settlement of Langmale to the settlement of Yangle Kharka about 6.5 km downstream. Peak discharge was estimated at 4400 ± 1800 m³ s⁻¹, and total flood volume was estimated at 1.3 × 10⁶ m³ of water. This study highlights the importance of conducting integrated field studies of recent catastrophic events as soon as possible after they occur, in order to best understand the complexity of their triggering mechanisms, resultant impacts, and risk reduction management options.
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Snow avalanches are a major natural hazard for road users and infrastructure in northern Gaspésie. Over the past 11 years, the occurrence of nearly 500 snow avalanches on the two major roads servicing the area was reported. No management program is currently operational. In this study, we analyze the weather patterns promoting snow avalanche initiation and use logistic regression (LR) to calculate the probability of avalanche occurrence on a daily basis. We then test the best LR models over the 2012–2013 season in an operational forecasting perspective: Each day, the probability of occurrence (0–100%) determined by the model was classified into five classes avalanche danger scale. Our results show that avalanche occurrence along the coast is best predicted by 2 days of accrued snowfall [in water equivalent (WE)], daily rainfall, and wind speed. In the valley, the most significant predictive variables are 3 days of accrued snowfall (WE), daily rainfall, and the preceding 2 days of thermal amplitude. The large scree slopes located along the coast and exposed to strong winds tend to be more reactive to direct snow accumulation than the inner-valley slopes. Therefore, the probability of avalanche occurrence increases rapidly during a snowfall. The slopes located in the valley are less responsive to snow loading. The LR models developed prove to be an efficient tool to forecast days with high levels of snow avalanche activity. Finally, we discuss how road maintenance managers can use this forecasting tool to improve decision making and risk rendering on a daily basis.
Full-text available
Coseismic avalanches and rockfalls, as well as their simultaneous air blast and muddy flow, which were induced by the 2015 Gorkha earthquake in Nepal, destroyed the village of Langtang. In order to reveal volume and structure of the deposit covering the village, as well as sequence of the multiple events, we conducted an intensive in situ observation in October 2015. Multitemporal digital elevation models created from photographs taken by helicopter and unmanned aerial vehicles reveal that the deposit volumes of the primary and succeeding events were 6.81 ± 1.54 × 10⁶ and 0.84 ± 0.92 × 10⁶ m³, respectively. Visual investigations of the deposit and witness statements of villagers suggest that the primary event was an avalanche composed mostly of snow, while the collapsed glacier ice could not be dominant source for the total mass. Succeeding events were multiple rockfalls which may have been triggered by aftershocks. From the initial deposit volume and the area of the upper catchment, we estimate an average snow depth of 1.82 ± 0.46 m in the source area. This is consistent with anomalously large snow depths (1.28–1.52 m) observed at a neighboring glacier (4800–5100 m a.s.l.), which accumulated over the course of four major snowfall events between October 2014 and the earthquake on 25 April 2015. Considering long-term observational data, probability density functions, and elevation gradients of precipitation, we conclude that this anomalous winter snow was an extreme event with a return interval of at least 100 years. The anomalous winter snowfall may have amplified the disastrous effects induced by the 2015 Gorkha earthquake in Nepal.
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Climatic time series for high-elevation Himalayan regions are decidedly scarce. Although glacier shrinkage is now sufficiently well described, the changes in precipitation and temperature at these elevations are less clear. This contribution shows that the surface area variations of unconnected glacial ponds, i.e., ponds not directly connected to glaciers, can be considered suitable proxies for detecting changes in the main hydrological components of the water balance on the south side of Mt. Everest. Glacier melt and precipitation trends have been inferred by analyzing the surface area variations of ponds with various degrees of glacial coverage within the basin. In general, unconnected ponds over the last fifty years (1963–2013 period) have decreased significantly by approximately 10 %. We inferred an increase in precipitation occurred until the mid-1990s followed by a decrease until recent years. Until the 1990s, glacier melt was constant. An increase occurred in the early 2000s, and in the recent years, contrasting the observed glacier reduction, a declining trend in maximum temperature has decreased the glacier melt.
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The Gorkha earthquake (M 7.8) on 25 April 2015 and later aftershocks struck South Asia, killing ~9,000 and damaging a large region. Supported by a large campaign of responsive satellite data acquisitions over the earthquake disaster zone, our team undertook a satellite image survey of the earthquakes' induced geohazards in Nepal and China and an assessment of the geomorphic, tectonic, and lithologic controls on quake-induced landslides. Timely analysis and communication aided response and recovery and informed decision makers. We mapped 4,312 co-seismic and post-seismic landslides. We also surveyed 491 glacier lakes for earthquake damage, but found only 9 landslide-impacted lakes and no visible satellite evidence of outbursts. Landslide densities correlate with slope, peak ground acceleration, surface downdrop, and specific metamorphic lithologies and large plutonic intrusions.
Significant elevation-dependent warming (EDW) of maximum near surface air temperature and diurnal temperature range (DTR) has been observed in Nepal (southern central Himalaya) until 2566ma.s.l., over the last four decades (1976–2015). During this period, on the average and across the entire country, maximum air temperature increased (+0.045 °C y−1, p < .001) more than minimum temperature (+0.009 °C y−1, p < .05) and, as a consequence, DTR also increased significantly (+0.034 °C y−1, p < .001). Maximum temperature increases have been observed during all seasons of the year. This warming pattern differs from the symmetrical one observed at global level in the same period, and it is in contrast to more prominent minimum temperature increases observed in the north of Himalaya (Tibetan Plateau). Furthermore, the near-surface air temperature change observed in Nepal contrasts the global evidence of main increasing trends occurring during the winter months. We point out that this asymmetric warming pattern could have more serious impacts in Nepal than in other regions of the world, considering the consequences of associated warm maximum-temperature extremes (heatwaves, hot days) on human life, increased primary production, and modifications in the hydrological cycle. We conclude sustaining that the observed EDW of maximum temperature and the DTR could be attributed to the monsoon weakening, namely to the reduced number of rainy days observed in the region during the last decades. These phenomena could have been accompanied by decreasing cloudiness and consequent increasing of daytime shortwave and decreasing of nighttime longwave incoming solar radiation.
Snow avalanche is a serious threat to the safety of roads in alpine mountains. In the western Tianshan Mountains, large scale avalanches occur every year and affect road safety. There is an urgent need to identify the characteristics of triggering factors for avalanche activity in this region to improve road safety and the management of natural hazards. Based on the observation of avalanche activity along the national road G218 in the western Tianshan Mountains, avalanche event data in combination with meteorological, snowpack and earthquake data were collected and analyzed. The snow climate of the mountain range was examined using a recently developed snow climate classification scheme, and triggering conditions of snow avalanche in different snow climate regions were compared. The results show that snowfall is the most common triggering factor for a natural avalanche and there is high probability of avalanche release with snowfall exceeding 20.4 mm during a snowfall period. Consecutive rise in temperature within three days and daily mean temperature reaching 0.5°C in the following day imply a high probability of temperature-rise-triggered avalanche release. Earthquakes have a significant impact on the formation of large size avalanches in the area. For the period 2011-2017, five cases were identified as a consequence of earthquake with magnitudes of 3.3≤ML≤5.1 and source-to-site distances of 19~139 km. The Tianshan Mountains are characterized by a continental snow climate with lower snow density, lower snow shear strength and high proportion depth hoar, which explains that both the snowfall and temperature for triggering avalanche release in the continental snow climate of the Tianshan Mountains are lower than that in maritime snow climate and transitional snow climate regions. The findings help forecast avalanche release for Citation: Hao JS, Huang FR, Liu Y, et al. (2018) Avalanche activity and characteristics of its triggering factors in the western Tianshan Mountains, China. Journal of Mountain Science 15(7). https://doi. 1398 mitigating avalanche disaster and assessing the risk of avalanche disaster.
In the mountains, human lives, property, infrastructures and ecosystems are threatened repeatedly by various hazards and dangerous processes. Natural hazards in the mountains include large-scale hazards such as earthquakes, droughts, eruptions and hurricanes, as well as others originated by small-scale mass movements of water, snow, ice, soil and rock. Dangerous natural processes include avalanches, debris flows, floods, landslides, rockfalls and other disastrous mass movements of soil and rocks. In mountainous regions these processes easily lead to casualties, injuries, destruction of goods and ecological damage. Humans pursue safety-seek to remove risks or at least to diminish and control them-through both systematic planning and intuitive measures. This article introduces some methods for evaluating the hazards and dangers and for assessing and reducing risks, and describes various types of preventive measures. It emphasizes the role of forests and land use planning in mitigating risk in mountainous regions. It advocates consideration of the traditional risk adaptive measures of mountain communities. The socio-economic conditions of mountain people play an important part in their vulnerability to risk and their ability to prevent and mitigate disaster. The article concludes with a call for integrated, cross-sectoral, participatory approaches to risk mitigation.