Heavy rainfall Wednesday through Thursday will lead to increased risk of landslides and flooding in Western Washington.
According to the National Weather Service, rainfall of 1 to 3 inches over the past couple days has increased soil moisture to high levels. Additional heavy rainfall of inches 1 to 3 inches is expected and this amount of rain will put extra pressure on soil instability. Rainfall induced landslides are possible during bursts of intense rainfall or when there is heavy rainfall over a period of a day or two. a gradually diminishing risk of landslides will continue for several days after the rain ends. Areas most susceptible to landslides under these conditions are steep coastal bluffs and other steep hillsides.
Also, heavy rain in the Olympics and Cascades could lead to flooding on a few rivers. Forecasters say 2 to 5 inches of rain has fallen in the mountains and some rivers are running higher than normal. According to the Weather Service, another wet storm system could bring similar amounts OF RAIN to the area Wednesday through Thursday. And snow levels are expected to climb to 5000 to 7000 feet. Computer models differ on the amount of precipitation but 2 to 5 inches seems most likely to fall over the Olympics and central cascades. The lowlands should receive one-half to two inches of rain. Forecasters say it is difficult to say which rivers will be impacted but the Skokomish, Chehalis and Snoqualmie rivers are at most risk of flooding.