STEVENS PASS — A winter storm may bring several feet of snow to mountain passes in the Cascades and Olympics over the next two days.
The National Weather Service upgraded its winter weather watch to a warning Monday.
The Cascades in Snohomish County could see two to four feet of snow. The Olympics may get one to two feet.
The warning is in effect 4 p.m. on Monday through 6 a.m. on Wednesday.
The snow level is expected to remain around 2,000 feet.
Highways could close at times for avalanche control, according to a National Weather Service memo.
Officials encouraged drivers to avoid mountain passes, except in emergencies.
Between two to four inches of snow is forecast for Stevens Pass during the day Monday, and eight to 12 inches at night.
On Tuesday, an additional foot of snow could fall on the pass during the day and 11 more inches at night.
Temperatures are expected to remain in the 20s throughout the week.
Meteorologists do not anticipate snow in the lowlands.