Three Types of Drought in the Pacific Northwest 2001, 2003,

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?
Composite of normal precipitation

• insufficient water to meet needs
• (Redmond, 2002)
• Defined in terms of its impacts
• Difficult to quantify

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

4
(No Transcript)
5
(No Transcript)
6
(No Transcript)
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?