Don Ryan / AP
Traffic veers around a wreck in snowy conditions after winter weather hit Beaverton, Ore. on Jan. 17, 2012. The National Weather Service has issued a winter storm warning for much of Ore. through Wednesday for heavy snow.
The Weather Channel reports on Tuesday morning that the dusting of snow that valley floors of the Pacific Northwest have received since Sunday are only a prelude to what could develop into one of the biggest winter storms to hit the region since 1985.
Tuesday night through Wednesday, a strong low-pressure system with copious amounts of moisture will approach the Northwest coast. This will set the stage for a potential major winter storm across the lower elevations and mountains of the Pacific Northwest. Travel could become dangerous or impossible in cities from the Canadian border down through Portland, Ore.
Msnbc.com reports I-90 at Snoqualmie Pass in the Cascade Mountains was shut down Tuesday morning for avalanche control.