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ERA5 geopotential heights (m) at 500 hPa and SAWS daily rainfall (mm) over South Africa during the period 6-21 April 2022.

ERA5 geopotential heights (m) at 500 hPa and SAWS daily rainfall (mm) over South Africa during the period 6-21 April 2022.

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Article
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Extreme rainfall associated with mid-tropospheric cut-off low (COL) pressure systems affected the entire east coast of South Africa during April 2022, leading to flooding and destruction of homes, electricity power lines, and road infrastructure, and leaving 448 people confirmed dead. Therefore, this study investigated the evolution of the two COLs...

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Context 1
... the developing (8-9 April) stage of the first system, some rainfall activities were observed over the central parts of the country due to the presence of the upper trough. Rainfall amounts between 20 and 80 mm were observed over the central and northern parts of the country as the system became fully developed on 10 April ( Figure 5). High accumulation of rainfall was observed over the southeastern parts of the country in KwaZulu-Natal Province, exacerbated by the identified easterly gale force winds which led to high moisture advection from the South Indian Ocean. ...
Context 2
... the developing (8-9 April) stage of the first system, some rainfall activities were observed over the central parts of the country due to the presence of the upper trough. Rainfall amounts between 20 and 80 mm were observed over the central and northern parts of the country as the system became fully developed on 10 April (Figure 5). High accumulation of rainfall was observed over the southeastern parts of the country in KwaZulu-Natal Province, exacerbated by the identified easterly gale force winds which led to high moisture advection from the South Indian Ocean. ...

Citations

... As was discussed before, predicting flood risk is a highly complex process because it depends on a large number of parameters such as rainfall, topography, and temperature mentioned by Mashao et al. (2022). The purpose of this study was to determine the most vulnerable area for flooding along with the south-west coastal region of Bangladesh, using historical data on water levels and demographic statistics. ...
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Flood is a frequent experience for the people living in Bangladesh, especially in the south-western region. But due to its complexity and multidisciplinary nature, flood management remains a very difficult task. This research focused on finding the most vulnerable areas to flooding for each polder within the Khulna and Satkhira districts since those areas can be identified as one of the most vulnerable areas to flooding. Water level data from fourteen stations of seven rivers (Sibsa, Rupsa-Pasur, Kobadak, Bhadra, Kobadak, Ichamati (Western Border), Betna-Kholpetua, and Satkhira Khal) were analyzed to calculate water levels for 2, 5, 10, 25, and 100-year return period applying normal distribution, extreme value type-I (EV-I), and log person type-III (LP-III) distribution methods. The EV-I distribution method was showing the best fit. The study revealed that station SW243 (Rupsa-Pasur River) in the Dacope region has the most extreme water level, station SW259 (Sibsa River) has the second-highest water level, and station SW254.5 (Satkhira Khal) in Satkhira Sadar has the third-highest water level for the return period of 100 years. A flood inundation map was prepared using the EV-I method’s 10-year return period value. The Analytic Hierarchy Process (AHP) was used to demonstrate the polders’ vulnerability depending on several factors. Overall, polder15 (Ghubra, Satkhira) is the most vulnerable polder, while polder 33 and polder 32 respectively are the second and third most vulnerable polders for flooding, both located in the Dacope region.
... Thus, any deluge of rainfall from these systems was exacerbated by human factors that led to flash flooding, mudslides, infrastructure collapse, etc. For example, rural-urban migration has led to illegal infrastructure developments, more sewer demands or the blocking of drainage systems and riverbank farming, especially in wetlands or on unstable platforms [63]. ...
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Every year, cut-off low (COL) pressure systems produce severe weather conditions and heavy rainfall, often leading to flooding, devastation and disruption of socio-economic activities in South Africa. COLs are defined as cold-cored synoptic-scale mid-tropospheric low-pressure systems which occur in the mid-latitudes and cause persistent heavy rainfall. As they occur throughout the year, these weather systems are important rainfall producing systems that are also associated with extreme cold conditions and snowfalls. An in-depth review of COLs is critical due to their high impacts which affect some parts of the country regularly, affecting lives and livelihoods. Here, we provide a comprehensive review of the literature on COLs over the South African domain, whilst also comparing them with their Southern Hemisphere counterparts occurring in South America and Australia. We focus on the occurrence, development, propagation, dynamical processes and impacts of COLs on society and the environment. We also seek to understand stratospheric–tropospheric exchanges resulting from tropopause folding during the occurrence of COLs. Sometimes, COLs may extend to the surface, creating conditions conducive to extreme rainfall and high floods over South Africa, especially when impinged on the coastal escarpment. The slow propagation of COLs appears to be largely modulated by a quasi-stationary high-pressure system downstream acting as a blocking system. We also reviewed two severe COL events that occurred over the south and east coasts and found that in both cases, interactions of the low-level flow with the escarpment enhanced lifting and deep convection. It was also determined from the literature that several numerical weather prediction models struggle with placement and amounts of rainfall associated with COLs, both near the coast and on the interior plateau. Our study provides the single most comprehensive treatise that deals with COL characteristics affecting the South African domain.
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Coastal regions are vital to numerous local economies and the national development of countries globally, including South Africa, due to their significant contributions to job creation, marine transportation, offshore drilling, resource extraction, fish cultivation, recreation and tourism. Despite these contributions to the coastal regions, the coastal communities are threatened by climate change in the form of sea level rise, floods, pollution, coastal erosion, changes to shorelines, extensive damage to critical infrastructure and destruction of coastal livelihoods. While these threats are increasingly hard to overlook, many governments and local administrators, including South Africa, have yet to prepare or implement strategies to meet these menaces adequately. Using mixed method approach of qualitative and quantitative, and extensive literature reviews, this paper explores the consequences of climate change on coastal livelihoods in South Africa. Our findings established that the country's coastal areas are under severe threats with high risks of submergence of floods, saltwater intrusion into surface and groundwater, increased erosion and overwhelmingly negative social and economic repercussions. This paper recommends a higher sense of urgency in addressing climate change threats and a much stronger implementation framework in climate change governance in the country, especially in the coastal zones.
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