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The Spokesman-Review Newspaper
Spokane, Washington  Est. May 19, 1883

Western Washington weather forecast has it all, from an ‘atmospheric river’ to wind, mudslides and mountain snow

By Christine Clarridge Seattle Times

SEATTLE – A river of rain, snow in the mountains, flooding, wind and dangerous beach conditions.

Is this a setup for a new disaster movie or simply another winter day in western Washington?

In a series of tweets, the National Weather Service of Seattle warned that Tuesday’s forecast “has it all.” A river of rain, or stream of atmospheric moisture, is a long, narrow region in the atmosphere – like a river in the sky – that transports most of the water vapor outside of the tropics, according to an explanation posted by the National Oceanic and Atmospheric Administration.

“These columns of vapor move with the weather, carrying an amount of water vapor roughly equivalent to the average flow of water at the mouth of the Mississippi River. When the atmospheric rivers make landfall, they often release this water vapor in the form of rain or snow,” NOAA said in a post on the phenomenon.

The main concerns with another round of heavy rain in and around Seattle, where the ground is already saturated, are landslides, mudslides and urban flooding.

“There are already some slides popping up in the area that we’ll be watching,” NWS Seattle meteorologist Courtney Carpenter said.

Southerly winds will pick up during the day as the system moves inland, the weather service predicts, with gusty winds 30 to 55 mph expected along the coast, the San Juans, and western Whatcom and Skagit counties with some power outages and tree damage possible.

Dangerous beach conditions are also forecast along the coast with waves of up to 17 to 22 feet, the weather service said.

At least eight roads were closed in King County around 7:30 a.m. due to water over the roadway or landslides. A landslide forced a road closure in Poulsbo around 6 a.m. Tuesday, and eight waterfront homes along Hood Canal near Poulsbo were evacuated because of a fire and a landslide that has destabilized the hillside and pushed trees into at least one home Monday, emergency officials said.

Two ferry sailings – 6:30 a.m. from Port Townsend and 7:15 a.m. from Coupeville – were canceled because of “high winds and rough seas.” Sounder train north line service is canceled Tuesday and Wednesday because of a mudslide and is expected to resume Thursday.

Carpenter said Thursday looks like it will be the only possibly dry day this week with a few more weather systems lined up for Friday and into the weekend, although none of those appear to be as heavy as the ones we had this past weekend.