The Colorado Drought 2001-2003: 2003: A Growing Concern Roger Pielke, Sr. Colorado Climate Center Prepared by Tara Green and Odie Bliss http://climate.atmos.colostate.edu
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2002 Drought History in Colorado A Brief Summary 3
EXAMPLES OF DROUGHTS Snow does not fall in the mountains until late January It is dry in April-July, but soaking rains occur in eastern Colorado in August The weather of 2001-2002 repeats for the next five years Colorado s mountains have 90% of average snow for the next 20 years. 4
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 Year 5
Drought Status on April 1, 2002 Entire State Dry Statewide Snowpack 53% of Average Bad, but not as bad as 1977 Optimism for a wet spring esp. in N. Colorado 6
But then came April Very warm especially in Mountains Very Dry Rapid Snowmelt Little Runoff 7
May also failed us Only one significant storm High evaporation rates Severe drought arrived!! 8
June 2002 Some heavy rains on plains but little plant growth Evaporation rates very high Many grass fires Even when some heavy rains did come to eastern Colorado in early June, the ground was so hard, the vegetation on grazed lands was so short and the rains fell for such a short period of time, that little of the moisture soaked in and vegetation remained parched. Grass fires popped up all over eastern Colorado, keeping local fire fighters on their toes. Extreme Drought in Mountains Forest Fires exploded 9
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 10
Widespread Drought By late July 2002, Colorado near epicenter of extensive regional drought Parts of nearly every state experiencing drought 11
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 12
The 1977 Drought 13
Total Precipitation Analysis September 2001 August 2002 Ranking by Station Climatic Stations Year of Record Rank Amount of Precipitation Grand Lake 1 NW 1940-2002 1 12.55 Taylor Park 1941-2002 1 10.42 Grand Junction WSO A 1892-2002 8 5.54 Meeker 1891-2002 7 10.37 Montrose No. 2 1896-2002 3 5.83 Mesa Verde NP 1923-2002 1 7.43 Del Norte 2 E 1940-2002 1 3.19 Center 4 SSW 1891-2002 1 2.44 Colorado Springs WSO 1892-2002 1 6.5 Pueblo WSO 1891-2002 1 3.8 Rocky Ford 2 SE 1892-2002 1 3.62 Cheyenne Wells 1897-2002 4 9.16 Akron 4 E 1905-2002 1 9.4 Leroy 7 WSW 1891-2002 3 10.58 Kassler 1899-2002 8 12.56 14
September 2002 Wet Weather at Last 15
Colorado Water Year 2002 (Oct. 2001-Sept. 2002) Precipitation Percent of Average for the 1961-1990 Averages 16
Where are we now? 17
Through 1999 18
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Colorado River Basin Snow Availability RIVER BASIN March 2, 2003 GUNNISON RIVER BASIN UPPER COLORADO RIVER BASIN SOUTH PLATTE RIVER BASIN LARAMIE AND NORTH PLATTE RIVER BASINS YAMPA AND WHITE RIVER BASINS ARKANSAS RIVER BASIN UPPER RIO GRANDE BASIN SAN MIGUEL, DOLORES, ANIMAS, AND SAN JUAN RIVER BASINS Number of Sites 11 of 12 25 of 27 15 of 16 13 of 13 13 of 14 6 of 6 10 of 10 15 of 15 Snow Water Equivalent % of Average 85 89 81 86 88 90 77 75 Source: http://www.wrcc.dri.edu/snotelanom/snotelbasin 23
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Accumulated Precipitaton (Inches) 35 30 25 20 15 10 5 Cheesman 2003 Water Year (through October '02-February '03) 30 Year Averages-1971-2000 Max Year - 1970 Min Year - 2002 Period of Record Average - 1904-2002 2003 Water Year 0 OCT NOV DEC JAN FEB MAR APR Months MAY JUN JUL AUG SEP 25
Accumulated Accumulated Precipitation Precipitation (Inches) (Inches) 35 35 30 30 25 25 20 20 15 15 10 10 5 5 0 0 Cheyenne Wells 2003 Water Year (through October '02-February '03) 30 Year Averages-1971-2000 30 Year Averages-1971-2000 Max Year - 1909 Max Year - 1909 Min Year - 1956 Min Year - 1956 Period of Record Average - 1971-2002 Period of Record Average - 1971-2002 2003 Water Year 2003 Water Year OCT OCT NOV NOV DEC DEC JAN JAN FEB FEB MAR MAR APR APR MAY MAY JUN JUN JUL JUL AUG AUG SEP SEP Months Months 26
Boulder 2003 Water Year (through October '02-February'03) Accumulated Precipitation (inches) 35 30 25 20 15 10 5 2003 Water Year 30 Year Averages-1971-2000 Max Year - 1995 Min Year - 1966 Period of Record Average - 1894-2002 2002 Water Year 0 OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP Months 27
3 Month SPI 28
12 Month SPI 29
48 Month SPI 30
COLORADO NEEDS What would be the impact today of historical droughts? What would be the impact today of paleodroughts? What if the 2001-2002 dry, warm weather reoccurred for 2002-2003? How can we make Colorado more resilient to droughts? What are the definitions of the multidimensional character of droughts. 31
Vulnerability Assessment A vulnerability assessment of risk to climate and other environmental stress is, therefore, more appropriate as guides to Policy Makers, than trying to predict only a subset of possible future climate conditions. 32
Image by Jan Null, CCM http://ggweather.com/winter0203.htm 33
Image by Jan Null, CCM http://ggweather.com/winter0203.htm 34
Image by Jan Null, CCM http://ggweather.com/winter0203.htm 35
In Conclusion Sept 1, 2001 to August 30,2002 was the driest for that period at most climate observing sites in Colorado. Over a several year time period, however, the current drought is a garden variety drought. It is not exceptional. Weather modification will not break a drought. At best, it slightly increases snowpack. The current drought is not a consequence of a warmer atmosphere. In fact, the Earth's atmosphere is no warmer today than it was in 1979. Models which have been used to predict climate a year or more in the future have demonstrated no skill in forecast ability. We should adopt vulnerability assessments as the preferred paradigm, rather than primarily focusing financial resources on prediction. 36
Colorado Climate Center Colorado State University Data and Power Point Presentations available for downloading http://climate.atmos.colostate.edu click on Drought then click on Presentations 37