BOARD01080

• Board Meeting Date: 1/27/2004
• Description: WSP Section - Native Species Trust Fund, Recommendations for FY 2004-05
• Board Meetings - Doc Type: Memo

.;colorado Water Resources Research Institute';

Summary of Colorado's Droughts and Prominent Wet Periods, 1890-1999.

NOTE: The dates in this summary are based on 12-month
water year (Oct-Sept) precipitation rotals from individual
weather stations and thus are not identical to the dates in
the table for 24-month periods, at the bottom of the page:

. 1890-1894 DRY Severe but brief drought in 1890,
particularly east of mountains, followed by a very wet
1891. Dry 1893 with severe drought 1894, again most
pronounced over eastern Colorado.

. 1898-1904 DRY Sustained and very severe drought
over southwestern Colorado. Worst drought on
record in Durango area. Some dry years elsewhere in
Colorado, but not as severe or sustained. Very wet
1900 northeast Colorado.

.

1905-1929 WET Longest recorded wet period in
Colorado history with greatest areal extent in 1905-
1906,1914-15, 1921, 1923 and 1927. Significant but
brief droughts did occur during this period, most
notably 1910-11, and 1924-25

.

1930-1940 DRY Most widespread and longest lasting
(and most famous) drought in Colorado recorded
history. Severe drought developed in 1931 and peaked
in 1934 and early 1935. Interrupted by heavy spring
rains in 1935 and more widespread heavy rains in 1938.
Culminated with one more extremely dry year in 1939
when several stations along the Front Range recorded
their driest year in history

.

1941-1949 WET Widespread wet weather, especially
1941-42, 1947 and 1949. Wet period interrupted with
dry mountain winters - 1944-45 and 1945-46 with very
low snowpack accumulation

.

1950-1956 DRY Extremely dry period statewide except
for one very snowy mountain winter 1951-52. Most of
state affected, and drought worse than the 1930s in
some areas such as the Front Range.

. 1959-1973 DRYIWET Interesting roller coaster ride
with alternating very wet and fairly dry periods and
large spatial variations. Local drought was prevalent
in 1959,1960, 1962, 1963,1964, 1966 and 1972. Very
wetweatherwasreportedin 1961,1965, 1969, 1970
and 1973 with episodes of flooding.

. 1974-1978 DRY Colorado's most recent period of
sustained multi-year drought culminating in the
record-breaking winter drought of 1976-1977, the
driest winter in recorded history for much Colorado's
high country and Western Slope.

. 1979-1980 WET Brief but pronounced wet period
with heavy winter snows helped replenish reservoirs.

.

1981 DRY An extreme but brief drought period from
the fall of 1980 into the summer of 1981. This
drought again took aim at the Colorado high country
and ski industry and initiated a huge investment in
snow making equipment. It also stimulated the
writing of the "Colorado Drought Response Plan"
and the formation of the "Water Availability Task
Force" which has been meeting at least once a
quarter each year since 1981.

.

1982-1999 WET Colorado's second longest
sustained wet period in recorded history and the
most drought free period since 1890. Extremely
abundant snowpack and surface water supplies 1982-
1987 -largest annual streamflow volumes this
century on several rivers. Interesting period, 1987-
1994 with only modest snow pack accumulation and
consistently below average streamflows, but with
low elevation precipitation above average reducing
demand for surface water. Significant but brief
drought in 1989 to early 1990 in southwest Colorado.
A brief growing season drought in 1994 in northeast
Colorado, and another localized drought over SW
Colorado from late 1995 into 1996. Very wet state-
wide in 1995, 1997 and 1999. The decade of the 1990s
has been the wettest in recorded history over much
of southeastern Colorado.

1957-1958 WET 1957 brought persistent widespread
drought-breaking precipitation across nearly all of
Colorado - wettest year in recorded history.

Table of Dry and Wet Periods for Colorado from the Fraction of Observing Sites.
Precipitation for 24 month SPI.

.

Date Dry Duration Date Wet Duration
1893-1905 X 12 years 1905-1931 X 26 years
1931-1941 X 10 years 1941-1951 X 10 years
1951-1957 X 6 years 1957-1959 X 2 years
1963-1965 X 2 years 1965-1975 X 10 years
1975-1978 X 3 years 1979-1996 X 17 years
15