Snow on the Olympics (S. Smith/PNPTC)

Increasing temperatures will result in less snowpack, especially at low- to mid-elevations where temperatures in western Washington have historically been near the freeze/thaw threshold. A decreased snowpack means less water from snowmelt during spring and summer months for many mountain streams, potentially reducing water availability and water quality as well as critical fish habitat. Reduced snow coverage increases the amount of bare ground that is exposed to runoff and therefore is likely to lead to increased sediment loads downstream.

Additionally, glaciers rely on snowfall to maintain their mass and insulate the ice against melting in the spring and summer months. A decrease in snowfall will lead to a reduction in glacier volume, which also has the potential to reduce summer flows in streams that rely on glacier melt.

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