Decreasing Snow Pack Levels in the PNW

Effects of Change in Snow Pack Levels in the PNW

Red circles indicate areas where snowpack percentages have decreased, blue circles indicate areas with  positive percent change. A general trend indicates an overall decrease in snowpack in the PNW from 1950-2000.
http://feww.wordpress.com/2010/04/30/verifiable-impacts-of-climate-change-part-ii/

In response to climate change, winter snowpack trends are also changing. Decreased winter snowfall translates to lower levels of snowpack couple with warmer winter temperatures leads to earlier melting dates at lower elevations.(Groom, Textbook)

Between 1950 and 2000, the depth of snow on the ground in early spring decreased at most measurement sites in the western United States and Canada. Spring snowpack declined by more than 75 percent in some areas, but increased in a few others.
 
A shift towards higher winter precipitation levels as well as decreased snow fall will cause western slope streams and rivers to have stronger winter flows as compared to spring or summer, summer levels will be reduced most significantly. The collateral effects of these changes include: threats to salmon populations who rely on steady stream levels to reach spawning grounds, as well as negatively effecting salmon lifecycles. (Climate Change Effects)