Forecasters say wet, loose slabs of snow could avalanche in the area that includes Mount Hood and Mount Rainier. Hikers and climbers are advised to stay out of the back country.
More mountain snow is falling as the latest storm moves into the Northwest.
Seattle has already set a rainfall record this spring.
The Weather Service says the new Seattle precipitation record from Feb. 1 through April 30 is 19.30 inches as of 9 a.m. Thursday. The old record was 18.97 inches set in 1972.