Snow + Water Supply
Nearly every location in Oregon has seen a
decline in spring snowpack, and it will continue
to significantly decline through mid-century,
especially at lower elevations.
Most of the Northwest will see decreases in April 1 snowpack in excess of 56%.
Oregon’s mountain snowpack serves myriad economic, ecological, and social functions, and the snowcapped volcanic peaks are part of the state’s cultural identity.
These changes in snowpack present a dual risk to the state.
In winter, increases in average streamflow will be the result of precipitation falling as rain instead of snow and rapid runoff, increasing flood risk in some basins.
Summer flows may be reduced by as much as 50% in some basins, presenting challenges to junior water rights holders, hydroelectric power generation, and those not served by reservoir or groundwater storage. Lower flows also impact important commercial and tribal fisheries.