Updated May 15, 2019
As the winter snowpack melts over the spring and summer, it serves as a significant source of water for farms, water suppliers, and fisheries. In fact, snowpack is the largest above-ground reservoir in the state. As the state's lead agency for water supplies, we pay close attention to snowpack and monitor it closely.
Snowpack in Washington tends to peak around early April. Snowpack conditions have deteriorated since April 1, declining from 80 to 52 percent of normal, averaged statewide. Several areas are now below 50 percent of normal.
Federal water supply forecasters predict lower available water supplies this summer in all areas except the southern part of the state. As weather conditions change, the water supply forecasts will evolve as well, but the chance for major changes in outlook will diminish as we get closer to the dry season.
Warmer than normal temperatures are causing the snowpack to melt fast. Nearly 40 percent of the snow at stations that measure snow water content in the mountains have melted out. In 2015, about 75 percent of the snow at stations had melted out by this time. Compared to the previous 30 years in early May, this year’s snowpack is about the sixth lowest on record.
An important part of our monitoring includes long-term projections. State and federal agencies partner with us to closely track snowpack conditions and monitor river and stream flows. Together we project water supplies for watersheds across the state.
We will regularly post information on this webpage about how snowpack, precipitation, and other factors may affect water supply forecasts.