Latest forecast as snow melts in the West
Scott Pattee, NRCS Water Supply Specialist
SPOKANE, WA (May 12, 2014) – April ushered in perfect, spring-like weather conditions in Washington State: warm and dry conditions early in the month quickly changed to cooler and wetter than normal. This cool pattern continues through the early part of May with forecasts trending toward warm and dry for the rest of the month, according to data from USDA’s Natural Resources Conservation Service in its May 2014 water supply forecast.
Washington, most of Idaho, Montana, Wyoming, and the northern parts of Colorado and Utah are expected to have near normal or above normal water supplies, according to the forecasts from NRCS’ National Water and Climate Center. Far below normal streamflows are forecast for the southern parts of Oregon and Utah, southwestern Idaho, California, Arizona, New Mexico and western Nevada. Many of these areas are experiencing drought.
The May 1 Washington statewide SNOTEL readings were 107 percent of normal but vary across the state. Snowpack increased at higher elevations; however, low- and mid-elevation snowpack has either melted completely or has reduced to below normal levels.
In western states where snowmelt accounts for the majority of seasonal water supply, information about snowpack serves as an indicator of future water supply. Streamflow in the West consists largely of accumulated mountain snow that melts and flows into streams as temperatures warm into spring and summer. NRCS scientists analyze the snowpack, air temperature, soil moisture and other measurements taken from remote sites to develop the water supply forecasts.
Plenty of precipitation and cool temperatures helped increase Washington streamflow forecasts by 5-20 percent this month. Forecasts vary from 86 percent of average for the Lewis River at Ariel to 139 percent of average for the Pend Oreille. April runoff varied greatly by basin and is often influenced this time of year by reservoir control, which may cause sudden changes in daily flows. Caution should be taken when working or playing in or near streams influenced by spring snowmelt.
NRCS’ streamflow forecasts are one of the tools used to assess drought conditions. USDA is partnering with western states to help mitigate the severe effects of drought on agriculture.
USDA leads the National Drought Resilience Partnership with the National Oceanic and Atmospheric Administration. In collaboration with state and community planners, this partnership coordinates resources for both short-term relief and long-term drought resiliency. Other federal partners in this effort include the Department of the Interior, Assistant Secretary of the Army for Civil Works, Federal Emergency Management Agency, U.S. Environmental Protection Agency and U.S. Department of Energy.
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 NRCS’ drought resources.
Since 1939, NRCS (previously Soil Conservation Service) 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 May Snow Survey and Water Supply Forecast map or view information by state.
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