The Colorado Drought of 2002 in Perspective Colorado Climate Center Nolan Doesken and Roger Pielke, Sr. Prepared by Tara Green and Odie Bliss http://climate.atmos.colostate.edu
Known Characteristics of Drought Drought Drought teases Colorado often Some Some portion of the state is in drought, based on common definitions and popular drought indices in at least 9 out of every 10 years
Severe Drought Occurrences Severe multi- year and widespread droughts occur a few times per century as evidenced by precipitation and stream flow records back into the 1880s, but also centuries farther back in history as revealed by tree rings and other "paleo indicators. Thru 1999 only
In hindsight, the 2002 first started with a dry fall and early winter in 1999 Then temperatures in 2000 were very warm The Path to the Drought of 2002
Spring of 2000 The months of April - June 2000 were very dry and hot. Sedgwick and Phillips counties were especially hard hit, and agricultural impacts were severe. Some later summer moisture did fall that helped dryland agriculture. Range and pasture conditions deteriorated steadily Entire summer was warmer than average -- the warmest summer in many years. Some severe ag. Impacts in Eastern Colo. Growing Season Precipitation as a % of Average
The 2002 Drought Monthly evolution By the end of 2001 Water Year soils were dry and reservoirs down to 93% of average (statewide)
January 2002 % of Average
March 2002 % of Average March was very dry but cold tempera- ture made it seem less droughty
Drought Status on April 1, 2002 Entire Entire State Dry Statewide Snowpack 53% of Average Bad, Bad, but not as bad as 1977 Optimism for a wet spring especially in Northern Colorado
April 1 Snowpack APRIL 1 SNOWPACK COLORADO STATEWIDE 160 148 146 Percent of Average 140 120 100 80 60 130 119 109 109 104 106 99 95 87 46 126 59 120 114 127 104 104 97 85 87 74 126 112 114 105 91 93 89 84 65 90 87 53 40 20 0 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 From the NRCS Snow Survey Division. Year
April 2002 % of Average
May 2002 also failed us Only one significant storm High evaporation rates Severe drought arrived!!
June 2002 % of Average
By late June 2002 Raging wildfires Extreme low streamflows Rapidly depleted reservoirs Severe agricultural impacts Wheat Cattle Irrigated crops in jeopardy Intense heat Urban water restrictions Hayman Fire Largest in Recent History
July 2002 % of Average
Widespread Drought By late July 2002, Colorado near epicenter of extensive regional drought Parts of nearly every state experiencing drought
U.S. Drought Most Widespread Since 1950s
August 2002 Pattern Changes More extreme heat early Another wildfire flare up Severe storms late in August Real relief in portions of the Eastern Plains But most of Colorado still in extreme drought Steamboat Springs Fire Photo from Steamboat Springs Fire Department
August 2002 % of Average 21
September 2002 Wet Weather at Last!
2002 Water Year in Summary Dry Dry all parts of State Dry Dry all seasons Steamflows lowest on record for many rivers Record Record summer heat Very Very high evaporation rates Far-reaching reaching impacts from minor inconveniences to extreme economic hardship
Water Year 2002 Departure from average, degree F 8 6 4 2 0-2 -4-6 Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Eastern Plains Foothills Mountains Western Valleys
Oct-Sept. 2002 WY % of Average
May-Sept 2002 Growing Season as Percent of Average
800 Cache la Poudre River Undepleted Flow (Preliminary) 700 Discharge (acre-ft * 1000) 600 500 400 300 200 10 year running average 100 0 1891 1901 1911 1921 1931 1941 1951 1961 1971 1981 1991 2001 Data from Northern Colorado Water Conservancy District 27
2000 2002 1998 45 40 35 30 25 20 15 10 5 0 Total evap. of Fort Collins (May-Sept) Sunken Pan Class A 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 Years 1960 evap. (in.)
1989 1999 1979 74 72 70 68 66 64 62 60 58 56 Fort Collins Summer Average Temperature (June - August) Summer Total 7 year running mean 1919 1929 1939 1949 1959 1969 Years 1909 1899 1889 Temperature (Deg. F)
What Happens Next We We have never experienced 2 consecutive extreme statewide drought years Past Past multi-year drought, characterized by one extreme year preceded and followed by other dry year Entire Entire State rarely all recovers quickly and at the same time Hope Hope for the best, plan for the worst!!
Dec. Feb. 2003 Temperature Outlook http://www.cpc.ncep.noaa.gov/products/predictions/multi_season/13_seasonal_outlooks/color/churchill.html
Dec. Feb. 2003 Precipitation Outlook http://www.cpc.ncep.noaa.gov/products/predictions/multi_season/13_seasonal_outlooks/color/churchill.html 32
Mar. May 2003 Temperature Outlook http://www.cpc.ncep.noaa.gov/products/predictions/multi_season/13_seasonal_outlooks/color/churchill.html
Mar. May 2003 Precipitation Outlook http://www.cpc.ncep.noaa.gov/products/predictions/multi_season/13_seasonal_outlooks/color/churchill.html 34
June Aug. 2003 Temperature Outlook http://www.cpc.ncep.noaa.gov/products/predictions/multi_season/13_seasonal_outlooks/color/churchill.html
June Aug. 2003 Precipitation Outlook http://www.cpc.ncep.noaa.gov/products/predictions/multi_season/13_seasonal_outlooks/color/churchill.html 36