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Drought in the western Great Plains, 1845-56. Impacts and implications

  • Lukas Climate Research and Consulting

Abstract and Figures

A sustained mid-nineteenth-century drought in the western Great Plains has been indicated by a tree-ring analysis of trees flanking the western Great Plains, and in tree-ring reconstructions of drought and streamflow for eastern Colorado and the Colorado Front Range. The development of new tree-ring chronologies for the western Great Plains, in combination with existing chronologies, now enables a more detailed assessment of the spatial and temporal characteristics of this drought. The analysis of a set of drought-sensitive tree-ring chronologies ranging from the northwestern Great Plains to central New Mexico indicates a core area of drought from south-central Wyoming to northeastern New Mexico for the years 1845-56. Drought was particutarly severe in the years 1845-48, 1851, and 1854-56, contracting and affecting smaller regions in intervening years. The impact of this drought on natural ecosystems and human activities is difficult to gauge because of the paucity of historical documents and the confounding effects of land use changes occurring over the same period. However, it is probable that this drought played a role in the decimation of bison herds in the second hall of the nineteenth century. Were it to occur today, this relatively small but persistent drought would have significant impacts on the Colorado Front Range metropolitan area and the agricultural regions of eastern Colorado.
Locations of tree-ring chronologies. Shaded area indicates core drought region for 1845-56. Chronology sites are numbered and correspond to those listed in Fig. 3. Chronologies selected were from species known to be sensitive to drought (ponderosa pine, Pinus ponderosa; Douglas-fir, Pseudotsuga menziesii; pinyon pine, Pinus edulis; and post oak, Quercus stellata), and were taken to be proxies of drought (generally winter/spring in the south grading to spring/early summer in the north). All but the three Montana chronologies (courtesy of D. Meko) were obtained or are now available from the World Data Center for Paleoclimatology's International Tree-Ring Data Bank (ITRDB; available online at In all but three cases (the Montana sites, where raw data were not available), raw ring-width measurements were used to generate treering chronologies (ARSTAN; Cook 1985) to ensure that the same standardization process and conservative detrending methods were used for all chronologies. Also included were 11 newly generated chronologies from isolated ponderosa pine, Douglas-fir, and pinyon pine woodlands growing in the Great Plains in Nebraska, eastern and central Colorado, and northeastern New Mexico (Woodhouse and Brown 2001). Except for the three Montana chronologies, residual chronologies, from which low-order autocorrelation presumed to be biological in origin has been removed (Fritts 1976), were used for this study. Also shown are locations of gridpoint PDSI reconstructions used in Fig. 4 (circled X symbols).
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The environment and culture of the western Great
Plains changed significantly over the course of
the nineteenth century. While Native Americans
were displaced and Euro-American settlers moved
across the region, the bison population, which at one
time numbered tens of millions (Flores 1991), suf-
fered an astoundingly abrupt decimation. The cause
of this near extinction has been hotly debated and at-
tributed to a range of factors that include the impacts
of both Native American and Euro-American land use
and hunting (Robbins 1999; West 1995, and refer-
ences within). Drought has been cited as a possible
contributing factor as well, but it is difficult to unravel
the roles played by each of these factors. In this pa-
per, we describe a mid-nineteenth-century drought
in part of the western plains—recorded by tree
rings—that appears to have persisted for more than a
decade in some parts of this region. We examine evi-
dence for this drought in historical accounts and its
contribution to the bison population’s demise. We
end by discussing the impacts such a drought might
have in the future.
The droughts of the 1930s and 1950s have long
served as benchmarks for severe and sustained
drought in the United States. Societal and ecological
impacts of these droughts were prolonged and well
documented. Although the spatial dimensions of the
two droughts were different, both had severe impacts
on the high plains of Kansas and Colorado (McGregor
1985). While this region is recognized as drought
prone (Karl and Koscielny 1982), the limited length
of instrumental records (100 yr or less) precludes a
full evaluation of the rarity of these droughts.
However, paleoclimatic records provide evidence of
climate for years prior to the keeping of instrumen-
tal records, and can be used to gauge the severity of
droughts in the twentieth century as well as for prior
centuries. In recent work, two new tree-ring-based
hydroclimatic reconstructions have been produced
for the eastern half of Colorado: a streamflow recon-
struction for the Colorado Front Range (Woodhouse
2001) and a Palmer Drought Severity Index (PDSI;
Palmer 1965) reconstruction for eastern Colorado
(Woodhouse and Brown 2001; Fig. 1). These recon-
Impacts and Implications
A relatively small, but severe and persistent drought occurred in the western Great Plains
during the mid-19th century, and may have contributed to the decimation of bison herds.
AFFILIATIONS: WOODHOUSE—NOAA Paleoclimatology Program,
and Institute of Arctic and Alpine Research, University of Colorado,
Boulder, Colorado; LUKAS—Institute of Arctic and Alpine Research,
University of Colorado, Boulder, Colorado; BROWN—Rocky
Mountain Tree-Ring Research, Fort Collins, Colorado
Paleoclimatology Program, National Geophysical Data Center, 325
Broadway, Boulder, CO 80305
DOI: 10.1175/BAMS-83-10-1485
In final form 2 May 2002
© 2002 American Meteorological Society
1486 OCTOBER 2002
structions indicate a period of remarkably sustained
drought and low streamflow lasting from approximately
1845 to 1856 that matched or exceeded the severity of
the droughts in this area during the 1930s and 1950s.
Another indication of western Great Plains drought
about this time is seen in the analysis of tree-ring chro-
nologies flanking the Great Plains (Meko 1992).
This period of drought occurred just prior to the
establishment of permanent weather-recording sta-
tions in the western Great Plains and thus is not docu-
mented in instrumental records. Although there have
been a number of tree-ring reconstructions of
drought for areas that include the Great Plains, a pe-
riod of drought as severe and persistent as indicated
in the Front Range and eastern Colorado reconstruc-
tions is not evident in large regional reconstructions
of the central United States (Fritts 1965, 1983; Stock-
ton and Meko 1983; Cook et al. 1996, 1997, 1999;
Woodhouse and Overpeck 1998). One reason it has
not been recognized in these reconstructions may be
an absence of high-resolution paleoclimatic data for
the eastern plains of Colorado. For the most part,
these past reconstructions utilized trees adjacent to,
but not in, the Great Plains to reconstruct climate, a
justifiable practice because tree growth typically re-
flects regional climate variability, and trees suitable for
climate reconstructions are rare in the Great Plains.
A comparison of a gridpoint reconstruction of
drought for eastern Colorado, which is part of a larger
reconstruction network, with the more recent east-
ern Colorado PDSI reconstruction indicates an im-
proved regional reconstruc-
tion with the inclusion of
Great Plains tree-ring chro-
nologies (Cook et al. 2002;
Woodhouse and Brown 2001).
Another reason is related to
the scale of drought. Studies of
large spatial patterns of drought
(Cook et al. 1996, 1997, 1999;
Woodhouse and Overpeck
1998) indicate discontinuous
periods of widespread, severe
drought during the 1840s and
1850s. In particular, the years
1845–47 and 1855–56 have
been reconstructed as severe
drought years for large areas of
the western and central United
States (Cook et al. 2002), but
the persistent drought seen in
the new Front Range stream-
flow and eastern Colorado
drought reconstructions is not seen in these large-
scale reconstructions. Studies focusing on regional
droughts in the eastern and southern Great Plains
(Iowa, Arkansas, Texas; Blasing and Duvick 1984;
Stahle et al. 1985; Stahle and Cleaveland 1988;
Cleaveland and Duvick 1992) do not show severe
drought conditions occurring from the mid-1840s to
the mid-1850s with the same consistency as seen in
the Colorado reconstructions either, suggesting this
period of persistent drought was limited in spatial
extent. Widespread drought conditions are indicated
somewhat later, overlapping with the Colorado
drought, in the decade centered around 1860 in re-
constructions for the central and southern plains
(Fritts 1983; Blasing et al. 1988; Stahle and Cleaveland
1988). In contrast, severe and sustained drought con-
ditions in the Front Range and eastern Colorado
abated after 1856 with hydroclimatic conditions re-
maining near or above average until 1861
(Woodhouse 2001; Woodhouse and Brown 2001).
greater detail the spatial and temporal characteristics
of the mid-nineteenth-century drought seen in the
two Colorado reconstructions, we examined a set of
60 tree-ring chronologies that range from eastern
Montana and western North Dakota, across the west-
ern Great Plains/Colorado Front Range to western
Colorado, central New Mexico, and Oklahoma, in-
cluding 11 newly generated tree-ring chronologies
from isolated woodlands growing in the western
FIG. 1. (a) Reconstruction of Middle Boulder Creek’s mean annual flow in
(cms) m3 s
1, 1710–1987 (Woodhouse 2001). (b) Reconstruction of spring/
summer droughts (May–Jun–Jul PDSI) for eastern Colorado, 1552–1995
(Woodhouse and Brown 2001). Series have been smoothed with a five-
weight binomial filter. The nineteenth-century drought in both series is
indicated by the striped bar. The 1930s and 1950s droughts are shaded for
comparison of duration and severity to the nineteenth-century drought.
Great Plains (Woodhouse and
Brown 2001; Fig. 2). Annual ring-
width values for each of the 60 chro-
nologies were ranked for the 285-yr
period, 1680–1964. Rankings were
evaluated for 1840–60, the years that
bracket the drought documented in
the Colorado Front Range stream-
flow and eastern Colorado drought
reconstructions. The years in each
chronology that fell within the low-
est 50th, 25th, and 10th percentiles
of growth were highlighted (Fig. 3).
The tree-ring chronology rankings
show a core area of low growth that
ranges from southern Wyoming to
southeastern Colorado/northeastern
New Mexico for the years 1845–56
(Figs. 2 and 3). Outside of this re-
gion, low growth occurred in subsets
of these years in western Colorado
(1845–48, 1851), the west/central
Dakotas and Nebraska (1845–48,
1855–56), and central New Mexico
(1841–43, 1845–48, 1851). In this
core area (here called eastern Colo-
rado, but as noted, with extensions
into southern Wyoming and north-
eastern New Mexico), severe
drought in 1842 was followed by wet
years in 1843 and 1844. The period
of sustained drought began in 1845
and was severe and widespread
throughout the core region in 1845–
48, 1851, and 1855–56. The extent of
low growth/drought was less in the
intervening years, 1849–50, 1852,
and 1854, but smaller core areas of
extreme low growth (25th percentile
or less) persisted in the northern and
central Front Range. The year 1853
was the least severe, with below-
median growth persisting only in
scattered sites, but with two sites still
exhibiting growth below the 25th
percentile. By 1857, above-median
tree growth returned to many areas,
and to virtually all areas by 1858. We
interpret this break in widespread
low growth in the eastern Colorado
region as an end to this period of
persistent drought. Below-median
tree growth in 1859 indicated a re-
FIG. 2. Locations of tree-ring chronologies. Shaded area indicates core
drought region for 1845–56. Chronology sites are numbered and cor-
respond to those listed in Fig. 3. Chronologies selected were from
species known to be sensitive to drought (ponderosa pine, Pinus pon-
derosa; Douglas-fir, Pseudotsuga menziesii; pinyon pine, Pinus edulis; and
post oak, Quercus stellata), and were taken to be proxies of drought
(generally winter/spring in the south grading to spring/early summer
in the north). All but the three Montana chronologies (courtesy of D.
Meko) were obtained or are now available from the World Data
Center for Paleoclimatology’s International Tree-Ring Data Bank
(ITRDB; available online at
In all but three cases (the Montana sites, where raw data were not
available), raw ring-width measurements were used to generate tree-
ring chronologies (ARSTAN; Cook 1985) to ensure that the same
standardization process and conservative detrending methods were
used for all chronologies. Also included were 11 newly generated chro-
nologies from isolated ponderosa pine, Douglas-fir, and pinyon pine
woodlands growing in the Great Plains in Nebraska, eastern and cen-
tral Colorado, and northeastern New Mexico (Woodhouse and Brown
2001). Except for the three Montana chronologies, residual chronolo-
gies, from which low-order autocorrelation presumed to be biologi-
cal in origin has been removed (Fritts 1976), were used for this study.
Also shown are locations of gridpoint PDSI reconstructions used in
Fig. 4 (circled X symbols).
1488 OCTOBER 2002
turn to dry conditions in parts of Colorado. Drought
prevailed again in eastern Colorado for three more
years (1861–63), but dry conditions were scattered
and only intermittent in the Front Range during these
The extent to which this mid-nineteenth-century
drought spread eastward into the central Great Plains
is unknown. Trees are scarce in this region, and tree-
ring collections in central Kansas have yielded mostly
young trees or samples that are difficult to date due
to numerous interannual rings (Woodhouse and
Brown 2001). Tree-ring chronologies from the south-
ern and eastern flanks of the Great Plains do exist and
have been used to reconstruct precipitation and
drought (Blasing and Duvick 1984; Blasing et al.
1988; Stahle and Cleaveland 1988; Stahle et al. 1985;
Cleaveland and Duvick 1992). Reconstructions for
Texas, Oklahoma, and Arkansas show severe and
prolonged drought peaking about 1860 (Blasing et al.
1988; Stahle and Cleaveland 1988; Stahle et al. 1985).
Drought starts in the mid-1850s in this area, over-
lapping with the drought identified in eastern Colo-
rado, but because of the difference in timing and lo-
cation, this period of drought appears to be of a
different nature than the 1845–56 Colorado
drought. Reconstructions for Iowa and Illinois also
show below-average moisture conditions in the
mid-nineteenth century but conditions are only
slightly below average during this period (Blasing and
Duvick 1984; Cleaveland and Duvick 1992). To illus-
trate the differences in timing and/or magnitude of
drought conditions suggested in the eastern and
southern plains reconstructions described above, the
gridpoint PDSI reconstructions from Cook et al.
(2002) for the eastern and southern Great Plains,
which use many of the same tree-ring data as well as
data from Kansas, were examined (locations shown
in Fig. 2, circled X symbols). A comparison of
gridpoint reconstructions for the eastern (southwest-
ern Iowa, northeast Kansas, the eastern Kansas and
Oklahoma border, eastern Oklahoma, and northeast-
ern Texas) and southern (central Oklahoma, north-
ern Texas) plains and the two eastern Colorado re-
constructions (eastern Colorado PDSI and Front
Range streamflow; Woodhouse and Brown 2001;
Woodhouse 2001) shows a difference in timing of
drought conditions (Fig. 4). Although there is evi-
dence of regional overlap, the Colorado drought is
more strongly centered on the late 1840s, while the
southern and eastern plains period of drought is cen-
tered on about 1860.
Although early instrumental records were kept at
forts in Kansas and Nebraska, most records are few
and fragmented until about 1858 (Mock 1991). Two
longer records exist from Fort Leavenworth and Fort
Scott in eastern Kansas and show several dry years in
the 1840s and 1850s, but no period of sustained
drought [the National Oceanic and Atmospheric
FIG. 3. Spatial distribution of low-ranking (narrow ring
widths) years for 60 tree-ring chronologies, 1840–70.
The chronologies were arranged by geographic region
to illustrate patterns of low growth, a proxy for
drought. The chronologies are grouped by region, from
roughly north to south: the northern and central Great
Plains, Colorado Front Range, eastern Colorado and
northeastern New Mexico, western Colorado, central
New Mexico, and Oklahoma. Annual ring-width indi-
ces for each of the 60 chronologies were ranked for
the 285 yr 1680–1964. Rankings are shown for 1840–
60 (major drought years outlined in black), the years
that bracket the drought documented in the Colorado
Front Range streamflow and eastern Colorado drought
reconstructions, and for the 1860s central Great Plains
drought, for comparison. The years in each chronology
that fell within the lowest 50th, 25th, and 10th percen-
tiles of growth were highlighted by red for a ranking
below the 10th percentile, orange for the 10th–24th
percentiles, yellow for the 25th–50th percentiles, and
white for the above-median ranking.
Administration’s (NOAA’s) Nineteenth-Century U.S.
Climate Data Set Project; available online at www.ncdc.]. Other limited
historical documents exist in the form of written ac-
counts by early explorers traveling across the Great
Plains in the eighteenth and nineteenth centuries. A
review of reports documenting blowing sand from the
Nebraska Sand Hills southward to northern Texas
indicates multiple observations of eolian activity from
about 1840 to 1865. It is, however, difficult to attribute
activation of sand dunes to a specific drought year or
set of years (Muhs and Holliday 1995). Along with the
tree-ring data from the southern and central flanks
of the Great Plains, these scant historical documents
suggest an eastern limit of drought conditions dur-
ing the period of sustained drought in eastern Colo-
rado, 1845–56.
DROUGHT AND BISON. Bison (Bison bison)
have been present in the Great Plains since at least the
last glacial period, and evolved under a climate regime
that included extensive periods of drought. Some re-
search suggests a decline or even absence of bison
remains in parts of the Great Plains during the mark-
edly dry mid-Holocene, from about 8000 to 5000 yr
B.P. (Dillehay 1974). (For the reader not familiar, B.P.
refers to “before the present.”) Other research clearly
establishes that bison persisted during a part of the late
Holocene that was far drier than the nineteenth cen-
tury as demonstrated by numerous hoofprints in sand
found in buried sand dune sediments in the west-
central Great Plains (Muhs 2000; D. H. Muhs 2001,
personal communication). Survival of the species dic-
tated the development of behavioral adaptations to
mitigate the impacts of drought, and likely included
some degree of migration to areas less affected by
drought (Flores 1991). A mass migration out of the
Great Plains is not indicated during the dry mid-
Holocene (Graham and Lundelius 1994), but we
speculate that bison likely migrated to locally moister
regions along riparian corridors.
In the last decade, the prevailing view that the
abrupt near extinction of the bison in the nineteenth
century was caused largely if not entirely by Euro-
American market hunting after the Civil War has
been challenged by some historians who have argued
that the decline began in the 1840s and resulted from
multiple interacting factors, including drought
(Flores 1991; West 1995; Isenberg 2000). Given the
survival of the species through periods of aridity last-
ing thousands of years, it is hard to believe a decadal-
length drought in the nineteenth century had much
of an impact on bison populations. However, the en-
vironment to which bison had long been adapted was
systematically disrupted by human activities in the
nineteenth century (Bamforth 1987).
Flores (1991), using older tree-ring data from
Nebraska, southern Wyoming, and the Colorado
Front Range that indicated generally dry conditions
in the southern and central Great Plains from 1846
to 1855 (Weakly 1943; Schulman 1956), proposed that
drought was one of several causes of the collapse in
bison populations across the Great Plains. This hy-
pothesis was developed further by West (1995), also
employing previous older dendroclimatological stud-
ies as well as historical accounts, who argued that gen-
FIG. 4. Tree-ring reconstructions for drought (PDSI) and
streamflow, 1800–99 with annual (black line) and
smoothed (five-weight binomial filter, red line) values.
Vertical shaded bars indicate eastern Colorado drought
(1845–56, dark gray) and southern/eastern plains
drought (1855–65, light gray line). (a) Colorado recon-
structions (Woodhouse 2001; Woodhouse and Brown
2001), (b) eastern Great Plains gridpoint drought re-
constructions from Cook et al. (2002), Nos. 91, 92, 93,
94, 95. (c) Southern Great Plains gridpoint drought re-
constructions from Cook et al. (2002), Nos. 82, 83.
1490 OCTOBER 2002
erally reduced rainfall in the 1840s and 1850s, com-
bined with increased grazing by both emigrants and
Indians, severely impaired the forage resources of the
uplands. Isenberg (2000) also attributed the bison
population demise to a combination of cultural and
environmental factors, including drought. The rela-
tively lush and wooded river corridors through the
western Great Plains had historically served as shel-
tered winter habitat and were likely year-round ref-
ugium for bison during drought as well (Flores 1991;
West 1995). Beginning in the early 1840s, large cara-
vans of both U.S. Army forces and Euro-American
settlers, with thousands of horses and other livestock,
traveled these corridors, severely reducing both for-
age and woodlands (West 1995). At the same time,
the Native American populations of the western Great
Plains, many of whom were relatively newcomers to
this area, with their numerous horse herds, were in-
creasing their usage of these same riparian corridors
in response to the regional bison hide market created
by newly established trading posts along the rivers
(West 1995; Isenberg 2000). As a result, bison would
have found much poorer conditions for subsistence
during a period when these riparian areas would have
been most critical. Studies during the 1930s and 1950s
found that grass cover in the shortgrass uplands was
dramatically reduced by drought (in one case from
90% to 20%) even in ungrazed areas (Malin 1947;
Tomanek and Hulett 1970); during the drought in the
mid-nineteenth century, conditions in the uplands
may well have been worse. Poor upland range condi-
tions and competition for riparian forage must have
exacerbated the impacts of what was, in the context
of the Holocene, a relatively minor drought. Thus,
even though bison had persisted through much worse
droughts in the mid- and late Holocene, human im-
pacts on the Great Plains environment likely altered
the bison’s ability to cope with drought in the nine-
teenth century (West 1995).
The concurrent timing of the drought and the de-
cline of the bison population lend further credence
to drought as a possible pivotal factor. Reports of the
reduction of bison numbers coincide, for the most
part, with drought years documented by tree rings.
The initial decline in the bison population was noted
as early as 1844 (see footnote 40 of Flores 1991). This
first report may have had less to do with drought than
with a reportedly “epic” spring snowstorm in eastern
Colorado in the spring of 1844 that apparently caused
a local die-off of bison and other ungulates (Benedict
1999). However, by the late 1840s, anecdotal evidence
from Kiowa painted robe calendars indicated few or
no bison for the years 1849–52 (Flores 1991), and
other historical accounts reflect a continued decline
through the 1850s (West 1995).
Although the cause for the decline in bison in the
nineteenth century remains a complex and much
debated subject, the drought conditions reflected in
the tree-ring records probably contributed to the de-
mise of Great Plains bison. Our study, by more clearly
describing the drought conditions at this time and by
locating a core of drought along and east of the Front
Range where bison populations apparently declined
first (West 1995), reinforces the work of Flores (1991),
West (1995), and Isenberg (2000) and adds even
greater support to the idea that drought contributed
to the bison population decline.
This relatively small nineteenth-century drought
would have had a very limited effect on the bison
population if human activities had not been a factor.
However, the severity and duration of this drought in
eastern Colorado qualifies it as a major drought for
this particular region. Although the size and length
of this drought have been matched and exceeded by
droughts in other areas, this drought is unique in
terms of its impact on this region, having been un-
matched here in at least the last three centuries. This
drought, were it to occur today, would have consid-
erable impacts now that the area includes a major,
rapidly expanding metropolitan area as well as large-
scale crop and livestock production. Large-scale
droughts have obvious social, economic, and ecologi-
cal impacts, but smaller-scale droughts may have sig-
nificant impacts as well, which may be aggravated by
location and timing.
An examination of small-scale droughts and their
relationships to periods of more widespread drought
is important for understanding why and where they
may be likely to occur. While drought conditions
were widespread during some of the years of this
nineteenth-century drought, they appeared to con-
tract into and persist in a core region in intervening
years. Major droughts in the twentieth century, while
more severe over larger areas, have displayed similar
episodic fluctuations. The 1930s drought period had
four distinct episodes of widespread dryness, and
similar episodes occurred in the 1950s drought
(Riebsame et al. 1991), with drought shrinking back
to core regions between years of expansion
(McGregor 1985). It is important to identify core ar-
eas within widespread droughts in order to assess pos-
sible significant regional impacts—and areas of drought
susceptibility—that are not noted in larger-scale analy-
ses. The core drought areas for both the mid-nine-
teenth-century drought described in this paper and
the 1930s drought included southeastern Colorado.
In the western Great Plains, late spring and sum-
mer are the most important seasons with regard to
drought, since this is when most of the annual pre-
cipitation occurs (Bryson 1966; Fritsch et al. 1986;
Helfand and Schubert 1995; Mock 1996). Rainfall
during this period can result from several different
circulation mechanisms, including frontal systems
drawing moisture from the Gulf of Mexico in the
spring (Hirschboeck 1991); and in summer, the Great
Plains nocturnal low-level jet (Tang and Reiter 1984;
Helfand and Schubert 1995; Higgins et al. 1997);
mesoscale convective complexes (Fritsch et al. 1986);
and less commonly, synoptic-scale upper-level distur-
bances (Helfand and Schubert 1995; Mock 1996).
Research suggests that conditions in both the Pacific
and Atlantic Oceans can lead to drought in the Great
Plains, directly or indirectly, by inducing perturba-
tions in patterns of atmospheric circulation and the
transport of moisture (Trenberth et al. 1988; Palmer
and Brankoviƒ 1989; Trenberth and Guillemot 1996;
Ting and Wang 1997). Although studies have linked
equatorial and northern Pacific conditions with
spring and summer precipitation in the Great Plains,
this relationship likely has more to do with Pacific sea
surface temperature influences on circulation than
direct transport of Pacific moisture (Ting and Wang
1997). On the other hand, drought in the Great Plains
is strongly linked to the flow of moisture from the
Gulf of Mexico in spring and summer, which is in-
fluenced by conditions in the Atlantic (Oglesby 1991;
Helfand and Schubert 1995). Enfield et al. (2001) sug-
gest that decadal-scale fluctuations in North Atlantic
sea surface temperatures (SSTs) are related to drought
in the central United States and also interact with
ENSO variability. Thus, drought in the Great Plains
may be caused by a number of different, but possibly
interrelated factors over an area that included both the
Atlantic and Pacific Oceans.
There is evidence to suggest that the drought con-
ditions in eastern Colorado in the mid-nineteenth
century were the result of several different overlap-
ping droughts, each related to different circulation
mechanisms. Recent work, using tree-ring and coral-
proxy climate data, suggests that the severe drought
centered around 1860 (roughly 1855–65) was linked
to an unusually long, cold ENSO event, possibly en-
hanced by low-frequency variations in the extratro-
pical Pacific (Cole et al. 2002). This event may have
been a cause of the drought centered around 1860
seen in reconstructions for the southern Great Plains.
However, the patterns of drought in the 1840s and
early 1850s reconstructed from tree rings are less con-
sistently representative of an ENSO cold event–
drought pattern (Cole et al. 2002; also see PDSI re-
constructions in Cook et al. 2002). This suggests that
while ENSO may have been a factor in the latter years
of the drought, other factors may have been respon-
sible in earlier years of the drought. Unfortunately,
no proxy records of Atlantic SSTs are yet available to
test relationships with regional drought during the
nineteenth century, but it is likely that a combination
of circulation patterns, including those influenced by
slowly varying conditions in both the Atlantic and
Pacific Oceans, was responsible for mid-nineteenth-
century drought conditions in the western Great
Plains. Further investigation of the associated sea sur-
face and atmospheric conditions for this time period
through an analysis of independent proxy data, such
as historical documents and other tree-ring data,
could yield more information about possible causes
of this mid-nineteenth-century drought.
CONCLUSIONS. This relatively small but persis-
tent nineteenth-century drought in the west-central
Great Plains likely influenced the cultural and ecologi-
cal history of this region. If a drought of this dura-
tion and severity were to occur here today or in the
future, impacts would be very different, but poten-
tially as significant. The state of Colorado, and south-
eastern Colorado in particular, has experienced sus-
tained, above-average precipitation for much of the
last two decades (McKee et al. 1999), a period also
characterized by rapid growth along the Front Range
urban corridor. In the Colorado Front Range, water
supply systems are commonly designed to handle the
“drought of record,” the most severe hydrologic event
in the instrumental record (Howe et al. 1994).
Although results of recent studies indicate that water
managers from a variety of Front Range municipali-
ties have considerable confidence in the reliability of
their current water supplies (Howe and Smith 1993),
how well would these cities and adjacent rural agri-
cultural areas endure a decade-long drought?
The importance of identifying and understanding
regional-scale drought should not be overlooked.
Since instrumental records exist for only the past 100
years in many areas, the potential to study regional
droughts based on instrumental data is limited. This
study points to the continued need for filling in spa-
tial gaps in high-resolution paleoclimatic data. The
lack of a finescale network of paleoclimatic data can
preclude detailed spatial analysis of past climate, but
in this study, new data and a regionally focused analy-
sis allow the identification of this regionally persistent
1492 OCTOBER 2002
drought. Global and large regional area reconstruc-
tions of past climate are very important for obtaining
an understanding of patterns of past climate and for
investigating possible large-scale controls. However,
studies of past climate at smaller regional scales are
of utmost importance especially in areas such as the
western Great Plains, where the cultural and ecologi-
cal history are entangled and disputed issues exist, and
the Colorado Front Range where an event the mag-
nitude of the mid-nineteenth-century drought would
have major societal, economic, and ecological impacts
were it to occur today.
ACKNOWLEDGMENTS. This project was supported
by NSF Grant ATM-9729751. We thank David Meko for
the Montana chronologies, and all contributors to the In-
ternational Tree-Ring Data Base who made this analysis
possible. Special thanks to Patricia Limerick, Elliott West,
and Dan Muhs for stimulating discussions on the role of
drought in the bison population decline. Thanks also to
Dan Muhs and David Stahle for their thorough and insight-
ful reviews of this paper.
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... The Dust Bowl of the 1930s is the best known of these events, with 95 percent of the southern Great Plains experiencing severe drought and associated economic hardship at its peak (Wilhite 2018). Evidence suggests, however, that the Dust Bowl was but one severe drought event in a series (Woodhouse, Lukas, and Brown 2002;Gallo and Wood 2015). Since the Dust Bowl, the area has been racked with periods of exceptional drought, including a drought in the 1950s described as "one of the more severe of record in the Southwest and southern Great Plains" (Nace and Pluhowski 1965, 50). ...
Despite the importance of land legacy effects on land use/land cover change (LULCC), historical data remain underutilized in analyses of social–environmental systems (SES). Drought, a slow-onset disaster, serves as an ideal case study to examine how multitemporal LULCC provides context for contemporary land use patterns. We use historical geographic information systems (HGIS) to analyze land ownership change, resource access, and land use in Cimarron County, Oklahoma, the epicenter of the Dust Bowl. We digitize archival county plats covering 1931 through 2014 into an HGIS. Through analysis of ownership information, we trace changes in familial and corporate landholdings during this period, exploring how different landowner types have changed over time. Aerial photography analysis helps to quantify the adoption of irrigation in relation to family survivability. Results show that families with larger landholdings in the 1930s were significantly more likely to persist through the Dust Bowl and continue owning land in the present. Access to the Ogallala Aquifer also increased the duration of land ownership. Corporate operators were most aggressive in adopting irrigation. Results raise questions of sustainability and uneven access to resources. We argue that land legacy has profound impacts nearly a century later. Further, SES studies can benefit from incorporating HGIS into their repertoire.
... For instance, the summer of 1855 was recorded as the "Summer of Sitting" in pictographs by Little Bear of the Kiowa in southern Kansas and western Oklahoma due to the extreme heat and widespread vegetation mortality (Gallo & Wood, 2015). The severe drought conditions of that period are considered as a potential factor in the ultimate demise of bison herds in the western U.S. (Woodhouse et al., 2002). Similarly, 1956 has been identified as the worst year of the 1950s Southwest Drought , the most severe drought on record in the southern and central Great Plains (Schubert et al., 2004), and the second most extensive North American drought year in the past millennium after 1934 (Cook et al., 2014). ...
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Plain Language Summary In 2012, the central United States experienced a “flash drought,” when rapid soil drying due to persistently low precipitation totals and high temperatures in late spring and summer caused billions of dollars in damages and agricultural losses. Such events are difficult to forecast because flash droughts can develop in a matter of weeks, and only a handful of flash droughts have been observed in recent decades, giving high uncertainty as to their likelihood. Here, we use tree rings to create two independent annual records of central United States soil moisture and the principal atmospheric circulation pattern known to cause flash droughts that extend back to the year 1500. Taken together, these records provide a new five‐century perspective on these crucial components of flash drought and reveal for the first time the long‐term behavior of central United States flash droughts, including frequency and cyclicity of exceptional events. We find that the instrumental record is a good representation of the long‐term likelihood of flash droughts. This apparent agreement with long‐term average conditions is largely by chance; however, as the reconstructions indicate large century‐to‐century variations in flash‐drought frequency and magnitude over the past 500 years.
... Flores (1991) pointed out that drought is 1 of contributing factors to the massive loss of the bison population in the nineteenth century. Woodhouse et al. (2002) believed the movement of the bison population is towards moister regions. So far, no attempt has been made to explore the relationship between droughts and bison grazing behavior. ...
As an iconic species linked to First Nations culture and economy in western North America, wild plains bison (Bison bison bison) currently rely on intensive management to persist. Yet, their presence maintains grassland ecological function, protects biodiversity and preserves important cultural heritage. Estimating carrying capacity is a key to achieve wildlife conservation without risking overall ecosystem health. Plains bison carrying capacity should be estimated to provide guideline for developing subsequent management plans. We reckoned that drivers of plains bison carrying capacity are forage availability and animal requirement, meanwhile its adjusting factors comprise spatio-temporal distribution and sustainable consideration. An integration of remote sensing and GIS can help to investigate variables of carrying capacity. Also Habitat Suitability Model built in Geographic Information System (GIS) is able to compile variables influencing carrying capacity. The review found multiple challenges of carrying capacity estimation in terms of implementing and practicing not only from remote sensing and GIS perspective. We expect that the advancement of remote sensors in accordance with modern GIS technology can provide timely effective carrying capacity estimation to achieve conservation goals of animal species as well as maintain sustainable ecosystems.
... We examined the spatial population dynamics and the role of short-and long-term climatic conditions for two threatened grassland birds (Lark Bunting, Calamospiza melanocorys, Chestnutcollared Longspur, Calcarius ornatus) that breed in the Great Plains of North America. The Great Plains are a dynamic ecosystem that evolved under periodic drought (Clark et al., 2002;Woodhouse, Lukas, & Brown, 2002) combined with frequent disturbance due to mammalian grazing (e.g., Bison Bison bison, Prairie Dogs Cynomys spp) and fire (Askins et al., 2007). Spatial variation in precipitation and the intensity of disturbance creates a mosaic of vegetation communities with different faunal species favouring particular conditions (Askins et al., 2007;Augustine, 2010;Samson, Knopf, & Ostlie, 2004). ...
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Aim The joint threats of climate and land‐use change require an understanding of how environmental variation influences species abundance and distribution. However, most species distribution models use static data and methods without considering how species respond over multiple temporal and spatial scales. Using a novel analytical approach, we show how multiscalar environmental variation drives spatial population dynamics of mobile species. Location Great Plains, North America. Methods We developed a spatial hierarchical model of abundance using long‐term citizen science data for two severely declining species (Lark Bunting, Calamospiza melanocorys, Chestnut‐collared Longspur, Calcarius ornatus). Specifically, we (a) compared regional variation in range‐wide abundance and population trends, (b) evaluated the influence of short‐term and long‐term drought on range dynamics and (c) tested whether regional population dynamics are spatially autocorrelated by environmental conditions occurring in geographically separated areas. Results Both species exhibited long‐term range‐wide declines >70% with contraction towards the range core. Lark Buntings showed opposing responses to environmental variation; regional abundance increased with wetter conditions during arrival on the breeding grounds but also with longer‐term (4‐year) drought conditions. Chestnut‐collared Longspurs showed no response to drought at either temporal scale. We found strong evidence that Lark Bunting abundance in the southern portion of the range increases with favourable environmental conditions leading to subsequent declines in abundance in northern regions. Main conclusions Our results highlight how (a) species can show opposing responses to the same environmental variable at different temporal and spatial scales, (b) sympatric species vary in their propensity to track environmental conditions and (c) for latitudinal migrants, environmental conditions along the migration pathway can influence settlement patterns with conditions in southern regions impacting abundance in the north. Our analysis indicates that an understanding of how global change impacts mobile species distributions will require range‐wide assessments incorporating response to environmental conditions across temporal and spatial scales.
... Calf composition of the Aishihik subpopulation was reduced by about 25% after a deep snow year in winter 2008/2009, when cows were observed to be in poor condition, and there was a recent die-back following a hard winter in the Chitek subpopulation (see Population Sizes and Trends). Woodhouse et al. (2002) and Isenberg (2000) have suggested severe regional droughts in the mid-19th century contributed to bison declines. Drought may be an issue for Plains Bison in Grasslands National Park where water courses and wetlands are a very small component of this mixed-grasslands landscape. ...
... In this study we used the first two methods. The droughts of the 1890s, 1930s, and 1950s have long served as benchmarks for severe and sustained drought in Kansas (Woodhouse et al. 2002). Although the spatial dimensions of these droughts were different, both the 1930s and 1950s had severe societal and ecological impacts on Kansas (Layzell and Evans 2012), thereby indicating high exposure and sensitivity to climate. ...
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... In the current study, PF is applied to the Little Washita watershed in central Oklahoma of the United States of America (USA). The watershed lies within the semi-arid Southern Great Plains of North America, an important agricultural region that is well known for its range of climate extremes, including severe droughts and heat waves (Namias 1982;Woodhouse et al. 2002;Schubert et al. 2004;Herweijer et al. 2007). The watershed encompasses approximately 720 km 2 of rolling terrain with minimum and maximum elevations of 323 and (Fig. 2b). ...
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Roots connect water stored beneath the Earth’s surface to water in the atmosphere. The fully integrated hydrologic model ParFlow coupled to the Common Land Model is used to investigate the influence of the root uptake formulation on simulated water and energy fluxes and budgets at local and watershed scales. The effects of four functional representations of vegetation water stress and plant wilting behavior are evaluated in the semi-arid Little Washita watershed of the Southern Great Plains, USA. Monthly mean latent and sensible heat fluxes differ by more than 25 W m−2 over much of the study area during hot, dry summer conditions. This difference indicates that the root uptake formulation has a substantial impact on simulated land energy fluxes and land–atmosphere interactions. Differences in annual evapotranspiration and stream discharge over the watershed exceed 14.5 and 55.5 % between simulations, respectively, demonstrating significant impacts on simulated water budgets. Notably, the analysis reveals that spatial variability in the sensitivity of local-scale water and energy fluxes to root uptake formulation is primarily driven by feedbacks between water table dynamics, soil moisture, and land energy fluxes. These results have important implications for model development, calibration, and validation.
... The current drought in Nebraska is minor compared to those determined from the recent geologic record (e.g., Woodhouse et al. 2002;Mason et al. 2004). Some climate-change models predict sharp declines in precipitation within this century in portions of the Great Plains (e.g., Gregory et al. 1997;Rosenberg 1999;Thomson et al. 2005). ...
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Recent decreases in rainfall and the accompanying decreases in groundwater levels since 1999 indicate heightened vulnerability to drought in Nebraska and the surrounding Great Plains. Precipitation across Nebraska during 2000-2005 ranged from 72% to 108% of the 30-year normal value, with fully 90% of 150 stations reporting below-normal precipitation. Simultaneously, groundwater levels declined more than 9 m in the most heavily impacted areas, most of which were already experiencing declines due to extensive irrigation development and low recharge rates. Thus, recovery from the drought and long-term intensive land use will be particularly challenging in densely irrigated areas of Nebraska. In contrast, contemporaneous groundwater-level changes in areas with little groundwater irrigation were comparatively modest. These observations demonstrate that drought mitigation efforts in the central and northern Great Plains must consider the combined effects of area-specific reduced recharge, local geohydrology (especially as it affects recharge), and increased groundwater withdrawals. © Copyright by the Center for Great Plains Studies, University of Nebraska-Lincoln.
The Great Plains region plays an important role in providing water and land resources and habitat for wildlife and livestock, crops, energy production, and other critical ecosystem services to support rural livelihoods. The semiarid conditions of the region and tight coupling of livelihood enterprises with ecosystem services creates a situation of increased sensitivity to climate changes and enhanced vulnerability among the rural communities and Native American nations across the region. Recent climate conditions associated with warming trends, and altered atmospheric flows have resulted in rapid onset of drought conditions and other extreme weather events across the region that are changing seasonal patterns of temperature and precipitation and warming trends. Projected climate changes provided in the fourth US National Climate Assessment indicate that potential warming and variability of precipitation will further increase drought and extreme weather events. Recent research and assessment efforts of current and projected climate changes in the Great Plains indicate that rural communities and ecosystems are becoming more vulnerable to changes associated with warming trends, droughts, and increased variability in precipitation. These climate changes are having differential impacts on ecosystem services that are critical to livelihood enterprises. Strategies for how resource managers and the research community can better collaborate and more effectively codesign and coproduce efforts to understand and to respond to these challenges are needed.
Most people would not consider north central Kansas' Waconda Lake to be extraordinary. The lake, completed in 1969 by the federal Bureau of Reclamation for flood control, irrigation, and water supply purposes, sits amid a region known-when it is thought of at all-for agriculture and, perhaps to a few, as the home of "The World's Largest Ball of Twine" (in nearby Cawker City). Yet, to the native people living in this region in the centuries before Anglo incursion, this was a place of great spiritual power and mystic significance. Waconda Spring, now beneath the waters of the lake, was held as sacred, a place where connection with the spirit world was possible. Nearby, a giant snake symbol carved into the earth by native peoples-likely the ancestors of today's Wichitas-signified a similar place of reverence and totemic power. All that began to change on July 6, 1870, when Charles DeRudio, an officer in the 7th U.S. Cavalry who had served with George Armstrong Custer, purchased a tract on the north bank of the Solomon River-a tract that included Waconda Spring. DeRudio had little regard for the sacred properties of his acreage; instead, he viewed the mineral spring as a way to make money. In Holy Ground, Healing Water: Cultural Landscapes at Waconda Springs, Kansas, anthropologist Donald J. Blakeslee traces the usage and attendant meanings of this area, beginning with prehistoric sites dating between AD 1000 and 1250 and continuing to the present day. Addressing all the sites at Waconda Lake, regardless of age or cultural affiliation, Blakeslee tells a dramatic story that looks back from the humdrum present through the romantic haze of the nineteenth century to an older landscape, one that is more wonderful by far than what the modern imagination can conceive.
Radiocarbon dates from prehistoric campsites and game-drive systems were used to develop a 3000-yr chronology of human population change at high altitude in the Colorado Front Range. Populations increased to record levels during the Late Prehistoric Period and then declined, tracking a probable warming-and-cooling trend. Superimposed on the long-term cycle were short-term oscillations that correlate closely with episodes of lichen snowkill inferred from the diameters of Rhizocarpon subgenus Rhizocarpon thalli in randomly selected 100-m² sample plots above tree limit. Transplant experiments and historical accounts of an epic storm in the spring of 1844 help understand the causes of lichen snowkill and its linkage to hunter-gatherers. During five periods of unknown duration between 1000 BC and AD 1230, vast areas above timberline remained snow covered for an average of at least 40 wk yr–1. Upslope snowstorms triggered by low temperatures and by cut-off low pressure systems in the southwestern United States are thought to have been responsible. The snow caused elk (Cervus elaphus), bighorn sheep (Ovis canadensis), and mule deer (Odocoileus hemionus) to starve on their springtime ranges in the eastern Front Range foothills. It damaged important forage species above timberline, discouraging surviving game animals and their human predators from returning to high altitudes for many decades. Springtime snow became less important after AD 1230, when northwesterly airflow intensified and lichen mortality was restricted to the floors of expanded snowpatches in topographic catchments. Low temperatures, summer drought, and epidemic disease were characteristic of this part of the archaeological record. The study demonstrates that changes in the frequency of archaeological radiocarbon dates in extreme environments can provide useful proxy evidence for climatic change and a precise chronological framework in which to interpret discontinuous paleoenvironmental data. It cautions that the East Slope of the Front Range is vulnerable to upslope snowstorms larger and more frequent than any that have occurred since the beginning of meteorological observations in the region.
Although many anthropologists have studied the Plains bison using historical documents, such studies often do not consider the information needed to make ecological sense out of the data these documents contain. Arguments about the “predictability” of herd movements are particularly weakened by this problem. Modern ecological research indicates that there are two critical factors which need to be addressed in reconstructing bison ecology on the Plains: the pattern of forage and other conditions which structure bison adaptations to a given local environment, and the effect of white expansion and predation upon these adaptations. This paper discusses several important aspects of the relationship between environmental conditions and bison ecology and presents information suggesting that historical records document a period during which bison adaptations were being seriously disrupted. Direct extrapolations from historic to prehistoric times which rely on these records are therefore uncertain.
Floods are caused by weather phenomena and events that deliver more precipitation to a drainage basin than can be readily absorbed or stored within the basin. The kinds of weather phenomena and events that cause floods include intense convective thunderstorms, tropical storms and hurricanes, extratropical cyclones and frontal passages, and rapid snowmelt. These individual meteorological processes are part of a larger climatic framework that determines: 1) the seasonal availability and large-scale delivery pathways of atmospheric moisture, 2) the seasonal frequency, typical locations, and degree of persistence of the weather phenomena that release the delivered moisture, and 3) the seasonal variation of climate-related, land-surface conditions that affect flood runoff, such as antecedent soil moisture or snow cover. -from Author
An analysis of faunal lists from 160 archaeological and paleontological sites in the Southern Plains reveals a success of long-term periods of presence and absence of the genus Bison in the region. Two absence periods are from about 6000-5000 B.C. to 2500 B.C. and A.D. 500 to A.D. 1200-1300. These long-term changes seem to indicate a combination of fluctuating bison population densities and range shifts. Certain previously documented prehistoric cultural events in particular subareas ofthe Southern Plains vicinity are examined in light of these data.
Tree ring indices from an expanded network of 17 white oak (Quercus alba) sites in eastern and central Iowa were used to reconstruct state average July Palmer hydrological drought index (PHDI), annual precipitation (previous August to current July), and other climate variables for 1640-1982. We removed nonclimatic variance trends caused by changing sample size and senescent growth. July PHDI correlated better with tree growth than annual precipitation. Occurrence of prolonged droughts throughout the reconstruction suggests that decades like the 1930s occur about twice per century in Iowa. Iowa climate is correlated with the Southern Oscillation Index (SOI) from June in the year of El Nino onset (Yr0) through the next February (Yr + 1), with negative SOI (El Nino) associated with wetter conditions. When the June (Yr0) to February (Yr + 1) average SOI reaches extremes greater-than-or-equal-to +1.0 or less-than-or-equal-to -1.0, it correlates significantly with observed and reconstructed July PHDI (r = -0. 37 and -0.56, respectively). Climate during solar cycles centered on sunspot minima alternates between wet and dry regimes that differ by an average of 1.21 units of observed July PHDI and 46.7 mm of annual precipitation for 1877-1982. The solar relationship has been stable since 1640. Combining solar and SOI influences in forecasts may improve prediction of Iowa climate.
The Palmer Index was used to compare the droughts of the 1930s and the 1950s in the central United States. A series of maps was produced to compare the droughts in terms of location, severity, and duration. The results indicated the 1930s drought lasted longer and consisted of three distinct waves. The 1950s drought, although shorter in overall duration, was actually more intense over a larger area for a longer period. There were changes in the size and configuration of the drought-affected area, but both droughts were especially persistent in a core region on the High Plains. A simple index of overall drought impact was developed based on the drought-affected area and the Palmer value from each climatic division. The probability of drought occurrence was calculated for each of the 76 climatic divisions in the study area. [Key words: drought, Palmer Index, Great Plains.]