Climate Change in Washington - Snow and Ice

Snow and Ice

Washington State is one of the nine contiguous states that has mountainous glaciers. These glaciers of the Olympic Range and the Northern Cascades produce 30 billion cubic feet (850,000,000 m3) of water every year. These glaciers are losing their size rapidly. Currently the Southern Cascade Glacier in Darington has lost two thirds of its volume. The glaciers in these ranges have, on average, decreased by 31 feet (9.4 m) and between 18 and 32% of their volume of water. An increase of 3.6 °F (−15.8 °C) will cause 65% to 75% of the glaciers to disappear in 40 years. The retreat of the glaciers will help to increase the decline. Glaciers reflect the incoming light from the sun. With less glacial cover the rocks on the mountain will heat up causing the surrounding frozen ice to melt even faster. Drainage basins that use glacial runoff will also be affected. Glaciers contribute to a base level of water that runs off after all of the new snow cover has melted. The Middle Fork River is likely to see huge decreases in its water levels in the coming years due to this issue. The Middle Fork provides a large amount of drinking water to Bellingham.

Precipitation in the Cascades has begun to be altered drastically. While the level of precipitation on the Cascades has not decreased since the 1950s, it has begun to shift from snow to ice when it falls. The level of glacial runoff is also on the uptick since the 1950s. The level of water that flows in to Puget Sound has decreased by 18% since 1949.

Water flows can be split up into three categories in Washington: Rain dominant, snow dominant, and transient snow melt watersheds. The change in water falling will make snow dominant regions appear to be more like transition rivers and transition more like rain dominant. Snow dominant regions have their highest water flow several months after their highest snow fall. Due to the increase in temp they will change and act more like transition which has two peak flows, one in the spring due to snow melt, and the other in the winter due to water falling as rain, not snow. The transition region now will act like rain regions which have their high points in river flows right after it rains.