Three Types of Drought in the Pacific Northwest – 2001, 2003, & 2005

1. Three Types of Drought in the Pacific Northwest – 2001, 2003, & 2005 Karin Bumbaco Philip Mote Office of the Washington State Climatologist University of Washington March 21, 2009

2. What is drought? • “insufficient water to meet needs” (Redmond, 2002) • Defined in terms of its impacts • Difficult to quantify Composite % of normal precipitation 1999-2008 water years compared to 1950-1995 normal

3. Methods • Yearly total precipitation and average temperature were ranked (1895-2005) for DJF and JJA for WA and OR • Monthly average streamflow data at 216 gauges in WA and OR (55 years) were also ranked relative to 2001 and 2003

7. 2001 • November to March had below average precipitation leading to low snowpack • 2nd driest DJF

8. 2001 OR • Record low precipitation in Portland, Astoria, Corvallis, and Eugene for the water year • 41-67% of normal • Driest water year in Hoquiam and Vancouver, 2nd driest in Spokane, 4th driest in Seattle WA

9. Rank of 2001 DJF streamflow with 55 yrs • Low streamflow in western WA and OR (many ranking 2nd to 1977) Fig: Rob Norheim

10. 2001 Impacts – Agricultural Drought • Pro-ratable junior water users in Yakima Basin, WA only received 37% of their entitlement • $130 million loss in agriculture revenues • Klamath Basin, OR had a showdown over water • Suckerfish vs. irrigated water for farmers • $157 million loss in agriculture revenues • Low river flows resulted in 5,300 MW loss in hydropower in WA ($3.5 billion)

11. 2003 • May through Sept had below average precipitation • 4th warmest DJF – low snowpack in OR • 2nd warmest and driest JJA

12. 2003 Impacts • 2003 JJA flows low in western WA and OR • Many forest fires in OR • Booth and Bear Butte fire • 3.7 million square meters • State of emergency Fig: Rob Norheim

13. 2005 - WA • DJF Precipitation was below normal (70-80%) • Snowpack was 20% of normal for the winter

14. 2005 Impacts - WA • Snowmelt-dominated streams were low • Drought declared March 10, 2005 • Hurt horticulture industry (lost 8-20% revenue in western WA) • Ski areas lost 1 million visitors (69% of average 10 yr visitation) = $43 million

15. 2005 - OR • More serious precipitation deficit in OR limiting snowpack like 2001 • “Drought plan” was implemented in Klamath Basin in March 2005 • Limited water to 2nd and 3rd priority holders (e.g. city parks) • Rains in March and April eased the burden

16. Relation to ENSO and PDO? • 2001 had cold ENSO, cold PDO, and dry Southwest • Indian Ocean warmth in 1999-2002 was associated with drought in large area of mid-latitudes including the PNW (Hoerling and Kumar, 2003) • Warmer Indian Ocean could be responsible for drought in recent years

17. Summary • Some droughts form in winter by low precipitation (2001) or a combination of low precipitation and high temperatures (2005) producing low snowpack • Impacts can be anticipated in most cases • Some form unexpectedly in summer (2003) • Points to the need for better timely information in summer • Implications for climate change

18. Thanks! Questions?