February storms increased snowpack in the northern half of the West but didn’t provide much relief for the dry southern half, according to data from USDA’s Natural Resources Conservation Service in its third 2014 water supply forecast.
East of the Continental Divide as well as parts of Washington, northern Oregon, northern Idaho and western Montana are forecast to have near-normal or above normal water supplies, according to the forecast from NRCS’ National Water and Climate Center. Snowpack in southern and eastern Oregon, California, Arizona, New Mexico and Nevada is still far below normal.
Although time is running out for snowpack recovery in drier areas, NWCC hydrologist Cara McCarthy said she won’t rule it out.
“We might have another miracle March,” she said, referring to late-season snowfall that has occurred in previous years. “During February we saw a dramatic recovery in the western Cascades of Washington.”
Some snow telemetry, or SNOTEL, sites in the eastern parts of Montana, Wyoming and Colorado received three times the normal amount of precipitation. The center will continue to monitor and forecast water supplies for the next three months.
“We’ll be keeping an eye out for potential stream flooding in those areas,” McCarthy said.
The Lake Powell reservoir, which provides water to parts of Nevada, Arizona and California, is now forecast to receive 109 percent of normal streamflow, up 15 percent from last month. When snow melts in the mountains, it flows down rivers and streams, and it will help relieve water shortages in those areas.
NRCS’ streamflow forecasts are one of the tools used to predict drought. In states where snowmelt accounts for the majority of seasonal water supply, information about snowpack is a key 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.
USDA is partnering with western states to help mitigate the severe effects of drought on agriculture. USDA is also co-leading the National Drought Resilience Partnership with the National Oceanic and Atmospheric Administration. In collaboration with state and community planners, the purpose of the partnership is to coordinate resources for both short-term relief and long-term drought resiliency. Other federal partners in this effort include the Department of the Interior, the Assistant Secretary of the Army for Civil Works, the Federal Emergency Management Agency, the Environmental Protection Agency and the U.S. Department of Energy.
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.