Regional News

Notable Snowpack Increase Strengthens Spring and Summer Runoff


Apr 12, 2016

All Washington State basins reported a notable increase in snowpack in March of 2016. This, on the heels of a winter that tended to be warm and rainy, was just what Washington State needed to bolster spring and summer runoff.

“There is still concern that the existing snowpack is further advanced then normal and could begin to melt more rapidly than hoped for. As the weather warms and the snow begins to melt in earnest be aware that streams and rivers will still be very cold and swift,” said NRCS Water Supply Specialist, Scott Pattee.

The latest NWS short-term forecasts are calling for warmer than normal with some chance of seasonal precipitation. Long-range forecasts for the spring continue to be warmer and dryer than normal. http://www.cpc.ncep.noaa.gov/ 

The April 1 statewide Snowpack Telemetry (SNOTEL) readings were 110 percent of normal. The Tolt River Basin reported the lowest readings at 77 percent of the 30-year median for April 1 and Trough SNOTEL near Wenatchee had the highest percentage with 205 percent. Most basins reported steady or a slight increase from last month with new snow particularly in the north Cascades.  Westside medians from SNOTEL, and April 1 snow surveys, included the North Puget Sound river basins with 105 percent of normal, the Central and South Puget river basins with 95 percent and 103 percent respectively, and the Lower Columbia basins with 117 percent of normal.  Snowpack along the east slopes of the Cascade Mountains included the Yakima area with 110 percent and the Wenatchee area with 108 percent.  Snowpack in the Spokane River Basin was at 95 percent and the Walla Walla River Basin had 127 percent of the long-term median.

The state received above normal precipitation for the month of March keeping year to date statewide SNOTEL averages above normal at 132 percent. The central and northeast areas of the state recorded the highest percentages in the state. Swift Creek SNOTEL near Mt. St. Helens received nearly 1 inch per day for a total of 29.1 inches and precipitation for the month of March.

Seasonal reservoir levels in Washington can vary greatly due to specific watershed management practices required in preparation for irrigation season, fisheries management, power generation, municipal demands and flood control. April 1 Reservoir storage in the Yakima Basin was 664,000-acre feet, 130 percent of average for the Upper Reaches and 196,000-acre feet or 130 percent of average for Rimrock and Bumping Lakes. The power generation reservoirs included the following: Coeur d’Alene Lake, 181,000 acre feet, 110 percent of average and 76 percent of capacity; and the Skagit River reservoirs at 64 percent of average and 33 percent of capacity.  Recent climate impacts and management procedures may affect these numbers on a daily or weekly basis.

Above normal temperatures continue to drive greater than normal daily runoff throughout the state. However a strong snowpack and precipitation accumulation are helping to keep streamflow forecasts near to above normal. April-September forecasts for some Western Washington streams include the Cedar River near Cedar Falls, 116 percent; White River, 114 percent; and Skagit River, 116 percent. Some Eastern Washington streams include the Yakima River near Parker 117 percent, Wenatchee River at Plain 105 percent; and Spokane River near Post Falls 98 percent. Volumetric forecasts are developed using current, historic and average snowpack, precipitation and streamflow data collected and coordinated by organizations cooperating with NRCS.

Since 1939, NRCS has conducted snow surveys and issued regular water supply forecasts. Since the late 1970s, NRCS has been installing, operating and maintaining an extensive, high-elevation automated system called SNOTEL, designed to collect snowpack and related climatic data in the western U.S. and Alaska.

View the latest Snow Survey and Water Supply Forecast information by state. Other resources on drought include the U.S. Drought Monitor. For information on USDA’s drought efforts, visit USDA Disaster and Drought Information. And to learn more about how NRCS is helping private landowners deal with drought, visit the NRCS website


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