April surge in snow has small impact for most states, Washington remains normal
Gina Kerzman, State Public Affairs Officer
SPOKANE, WA (MAY 17, 2013) – May measurements confirm April forecasts: NRCS hydrologists predict normal to above average spring and summer water supply for Washington State.
April saw additional mountain snow in Washington as well as above normal runoff. The chilly, wet April weather not only bolstered mountain snowpack but also prevented early snowmelt; however spring brought above normal temperatures since May 1. Weather forecasters are now calling for a dry spring and summer with probable chances of near to above normal temperatures.
“For much of the West, April was wetter than January, February and March combined,” said NRCS Meteorologist Jan Curtis.
During the month of April, the National Weather Service and Natural Resources Conservation Service (NRCS) climate stations reported much above normal precipitation in all river basins in Washington, helping to maintain near to slightly above average water year totals.
Streamflow forecasts vary from 72 percent of average for the Snake River below Lower Granite Dam to 155 percent of average for S.F. Tolt River near Index. Volumetric forecasts are developed using current, historic and average snowpack, precipitation and streamflow data collected and coordinated by organizations cooperating with NRCS. Above normal rainfall throughout the month of April combined with normal spring reservoir operations contributed largely to mostly above normal runoff.
Washington State may be alone in this designation; however, as USDA Secretary Vilsak deemed many counties in Western states as eligible for USDA drought assistance.
Water resource managers face difficult decisions because of this shortage. Western states should prepare for potentially increased vulnerability to forest and rangeland fires and mandatory water restrictions. In addition, wildlife that depends on surface water is going to suffer.
“For the rest of the West, there is no silver lining,” NRCS Hydrologist Tom Perkins said. “I think it’s going to be a long, hot, dry summer.”
NRCS’ National Water and Climate Center monitors soil moisture with its SNOw TELemetry (SNOTEL) and Soil Climate Analysis Network (SCAN) networks. These sensors gather soil data that helps NRCS better monitor drought development.
“Although NRCS’ streamflow forecasts do not predict drought, they provide valuable information about future water supply in states where snowmelt accounts for the majority of seasonal runoff,” said Perkins.
In addition to precipitation, streamflow in the West consists largely of accumulated mountain snow that melts and flows into streams as temperatures warm into spring and summer.
The May forecast is the fifth of six monthly forecasts. The forecast compares the current level of water content in snowpack in the 13 Western states with historical data to help the region’s farmers, ranchers, water managers, communities and other stakeholders make informed decisions about water use and future availability.
NRCS scientists analyze snowfall, air temperature, soil moisture and other measurements taken from remote climate sites to develop water supply forecasts.
Since 1935, NRCS has conducted snow surveys and issued regular water supply forecasts. NRCS installs, operates and maintains an extensive, automated system called SNOTEL, designed to collect snowpack and related climatic data in the Western United States and Alaska.
View May’s Snow Survey Water Supply Forecasts map or view information by state.
Other resources on drought include the U.S. Drought Monitor and U.S. Seasonal Drought Outlook map. For information on USDA’s drought efforts, visit www.usda.gov/drought. To learn more about how NRCS is helping private landowners deal with drought, visit the NRCS site.
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