Analysis of Future Snow Conditions for the National Climate Assessment

The Third National Climate Assessment Report is under development. To support this effort, regional analyses of climate conditions were conducted, focusing on both historical trends deduced from observations and future projections derived from climate model simulations. A recent project on snowfall trends generally found declining total snowfall in the western U.S. at cooperative observer sites. Since the 1990s, the area with extreme high seasonal snowfall has been well below the long-term mean. Climate model simulations show substantial future warming throughout the west. Precipitation is simulated to decrease in the Southwest and increase in the Northwest and Alaska. These results suggest future declining snowpack in the southwest.