The Colorado Drought of 2002 in Perspective

Transcription

1 The Colorado Drought of 2002 in Perspective Colorado Climate Center Nolan Doesken and Roger Pielke, Sr. Prepared by Tara Green and Odie Bliss

2 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

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4 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

5 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

6 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

7 The 2002 Drought Monthly evolution By the end of 2001 Water Year soils were dry and reservoirs down to 93% of average (statewide)

8 January 2002 % of Average

9 March 2002 % of Average March was very dry but cold tempera- ture made it seem less droughty

10 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

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12 April 1 Snowpack APRIL 1 SNOWPACK COLORADO STATEWIDE Percent of Average From the NRCS Snow Survey Division. Year

13 April 2002 % of Average

14 May 2002 also failed us Only one significant storm High evaporation rates Severe drought arrived!!

15 June 2002 % of Average

16 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

17 July 2002 % of Average

18 Widespread Drought By late July 2002, Colorado near epicenter of extensive regional drought Parts of nearly every state experiencing drought

19 U.S. Drought Most Widespread Since 1950s

20 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

21 August 2002 % of Average 21

22 September 2002 Wet Weather at Last!

23 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

24 Water Year 2002 Departure from average, degree F Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Eastern Plains Foothills Mountains Western Valleys

25 Oct-Sept WY % of Average

26 May-Sept 2002 Growing Season as Percent of Average

27 800 Cache la Poudre River Undepleted Flow (Preliminary) 700 Discharge (acre-ft * 1000) year running average Data from Northern Colorado Water Conservancy District 27

28 Total evap. of Fort Collins (May-Sept) Sunken Pan Class A Years 1960 evap. (in.)

29 Fort Collins Summer Average Temperature (June - August) Summer Total 7 year running mean Years Temperature (Deg. F)

30 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!!

31 Dec. Feb Temperature Outlook

32 Dec. Feb Precipitation Outlook 32

33 Mar. May 2003 Temperature Outlook

34 Mar. May 2003 Precipitation Outlook 34

35 June Aug Temperature Outlook

36 June Aug Precipitation Outlook 36