The National Weather Service reduced flood forecasts along at least one major river, the Skagit, after rapidly rising rivers caught hundreds of residents by surprise in low-lying areas. Mud and rock slides blocked a number of highways and delayed an Amtrak passenger train.
Flood warnings continued on 14 Western Washington rivers. The weather service said the steady drenching should change to rain showers by Tuesday afternoon, with Wednesday and Thursday dry before another Pacific weather system brings more rain and wind on Friday.
One record fell by nightfall Monday as the flow on the south fork of the Snoqualmie River east of Seattle reached 51,970 cubic feet per second, exceeding the mark of 50,000 cfs set in December 1996. Forecasters said the river flow could reach 69,000 cfs before subsiding.
Helicopters and hovercraft were pressed into rescue service as Gov. Chris Gregoire declared a state of emergency Monday for 18 counties, authorizing mobilization of the National Guard and directing the state Emergency Management Division to coordinate assistance after more than 6 inches of rain fell in 24 hours in some areas.
Tens of thousands of schoolchildren got the day off from classes or had to do without bus service.
Stampede Pass in the Cascades east of Seattle had more than 8 inches of rain in a 24-hour period ending Monday afternoon, and Seattle-Tacoma International Airport recorded nearly 4 inches.
Rainstorms propelled by air currents from Hawaii, a pattern known as the Pineapple Express, also caused severe flooding in southwest British Columbia, forcing the evacuation of about 200 people in the Fraser River valley near Chilliwack, about 60 miles east of Vancouver.
The weather service warned officials in Skagit County to expect worse conditions than in 2003, when flooding caused $17 million in property damage in Concrete and 3,400 households were evacuated.
Shortly before midnight high-water predictions along the Skagit River were reduced to 40.5 feet from 43.83 feet at Concrete, where the crest was expected early Tuesday, and to 36 feet from 38.07 feet downstream early Wednesday at more populous Mount Vernon.
Mount Vernon Mayor Bud Norris declared a civil emergency late Monday, and volunteers worked through the night to build a sandbag wall downtown next to the river.
Amid earlier warnings of record flooding, more than a dozen Guard personnel were sent late Monday to rescue an unknown number of people in Skagit County, and another 150 troops were expected Tuesday, county spokesman Don McKeehen said.