Warm weather shrinks April snowpack

BOZEMAN (AP)

Montana's mountain snowpack fell to 68 percent of normal in April, after unseasonably warm temperatures, officials with the Natural Resources Conservation Service said. Snow levels fell by one to three percent west of the Continental Divide and by five to seven percent east of the Divide, said Roy Kaiser, a water supply specialist with the agency. “These conditions are due mostly to the variable April weather,” he said. “There were both record high temperatures and storms that yielded significant snow water increases.” Snowpack is 74 percent of average in the Columbia River basin, and 63 percent of average in the Missouri and Yellowstone river basins. It was 75 percent of average in the St. Mary basin and 76 percent of average in the St. Mary and Milk basins. Statewide snowpack was 75 percent of normal in March. As the snow melts it feeds into rivers, streams and reservoirs. River flows affect recreation, irrigation and in some cases municipal water supplies. This spring's quickly melting snowpack has lowered state streamflow forecasts through July, and officials said rainfall will be key to keeping rivers and streams healthy through the summer. “It's another one of those years we just have to get through,” Kaiser said. Streamflow is now expected to run between 62 and 74 percent of average statewide. Streamflows west of the Divide are estimated to average between 72 and 87 percent, while those east of the Divide were forecast between 54 and 69 percent. “Below average May 1 snowpack and higher than average snowmelt may mean that streams could reach their lowest flows in midsummer,” Kaiser said. “Streams and rivers without storage could be affected earlier than those with lake and reservoir storage.” The U.S. Climate Prediction Center is forecasting a cooler and wetter than average May.