March 18 weekly drought update
We're gathering the latest drought information and sending it out every week.
Drought data summary:
We are seeing some minimal snowpack improvements though much of the improvement was lost over the warm weekend. From last week’s report:
Upper Columbia from 68% to 67% - Down 1%
Central Columbia from 71% to 70% -Down 1%
North Puget Sounds from 64% to 62% - Down 2%
Central Puget Sound from 66% to 70% - Up 4%
South Puget Sound from 67% to 69% - Up 2%
Lower Yakima from 63% to 65% - Up 2%
Olympics went from 57% to 59% (after jumping to 61% on Friday) – Up 2% but lost gains made during the week.
This time of year we normally see an ongoing buildup of snowpack as winter draws to a close. We are glad to see all basins out of the red (below 50%) but are still concerned about the impacts for water availability in summer.
On this date in 2015, Statewide SWE was 24% and the Olympics were at 9%.
In 2005 today, Statewide SWE was 19% and the Olympics were at 16%.
Between the NW River Forecast Center and The Climate Prediction Center, there are different forecasts for the next 8-10-14 days, but regardless of the level of temperature and precipitation in the next two weeks, we are unlikely to make up for existing deficits.
We continuing to encourage water users to plan for a drier than normal year. While our Water Year to Date numbers may look promising, when water is available is still impacted by the snowpack drought in some watersheds, especially those with a deeper deficit from last year’s drought conditions.
Data indicates that we are in a snowpack drought for several areas of the state.
Drought declaration status:
The Water Supply Availability Committee (WSAC) met February 28 and will meet again March 27. (February Materials and Recording). At the March meeting we anticipate revisiting the question of if the hydrologic threshold has been met in additional geographic areas beyond those in the exiting drought declaration.
We currently have the existing drought emergency declaration in place for the same 12 watersheds declared in July 2023.
Drought definition – “The water supply for a geographic area, or for a significant portion of a geographic area, is below seventy-five percent of normal and the water shortage is likely to create undue hardships for water users or the environment.” (RCW 43.83B & WAC 173-166).
Data roundup:
NRCS/USDA – Snowpack data
72% Statewide (Same as last week) Snow Water Equivalent (SWE); By Basin: WA Report or by maps: SWE by Basin – PDF (attached) or Interactive map
90% = Water YTD precipitation (Down 2% from last week).
Why does “SWE” matter – USDA Factsheet
NW River Forecast Center – Updated
Streamflow Water Supply forecast – Updated - Ranking based on comparison to historical record – The attached screenshot highlights that areas in NW, Central Cascades and the Olympics are forecasted to rank among the lowest years measured.
Office of the WA State Climatologist – Updated
The March precipitation outlook indicates higher chances of below normal precipitation statewide. El Niño is still likely to transition to neutral conditions during the April-May-June period (79% chance). The Climate Prediction Center is also issuing a La Niña Watch, showing a higher likelihood of La Niña (55% chance) compared to neutral (42% chance) by June-July-August.
Bureau of Reclamation (BOR)
Yakima River system (Keechelus, Kachess, Cle Elum, Bumping, Rimrock) is at 41% of capacity and storage is at 64.7% of average.
Last updated: March 11, 2024; Next update: March 12 (daily).
March 4 BOR forecast (next BOR forecast April 4): The U.S. Bureau of Reclamation (BOR) projected Monday that Yakima River basin irrigators with junior water rights will receive 72% of their full allotments between April and September. Allotments could drop to as little as 47% if the weather is dry and warm (news articles linked below).
We'll be sending this update every week to keep you informed about drought conditions statewide. To learn more about water supply in Washington visit our statewide conditions page.