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,

What is drought? “insufficient water to meet needs” (Redmond, 2002) Defined in terms of its impacts Difficult to quantify water years compared to normal Composite % of normal precipitation

Methods Yearly total precipitation and average temperature were ranked ( ) 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

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

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

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

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) 10

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

2003 Impacts 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

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

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 14

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

Relation to ENSO and PDO? 2001 had cold ENSO, cold PDO, and dry Southwest – Indian Ocean warmth in 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 16

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 17

Thanks! Questions? 18