The Snoqualmie Valley could see flooding overnight on Saturday and into Sunday morning as heavy rains are expected in the area this weekend.
The National Weather Service river forecast tool predicts that rivers will reach flood levels overnight on Saturday, and peak by 10 p.m. on Sunday night. Areas around Carnation are expected to see the highest water levels.
Cynthia Krass, director of the Snoqualmie Valley Preservation Alliance, said they were expecting to see flooding in areas around the valley. The Alliance operates several additional river gauges which help augment the National Weather Service ones.
As of noon on Dec. 17, the river at Carnation was expected to reach 57.5 feet, well above the 54 foot flood level. At the Snoqualmie gauge, water levels were expected to reach 16.5 feet, rising above the flood level of 13.43 feet.
Joan Pliego, public information officer for the city of Snoqualmie, said they don’t expect to see much flooding in the city, based on current predictions.
“Usually, we don’t see any problems until around flood phase four,” she said.
Flows at the Snoqualmie gauge are expected to reach some 35,000 cfs, beneath phase four flow levels.
Pliego said city employees are closely monitoring the river gauges, and will send out alerts based on changing conditions. If needed, the city will provide sandbag materials for residents, but she didn’t expect they would be needed this weekend.
At the county level, Doug Williams, media relations coordinator for the Department of Natural Resources and Parks, said it’s hard to predict how severe a flood will be.
The county will be deploying its flood warning center, that opens whenever flows start getting high. Usually, it’s held in downtown Seattle, but due to the pandemic, it will be operating remotely at first. If flooding gets severe enough, the center will move in-person.
Rain in December is expected in Puget Sound, but the snow level is expected to be high on Saturday night. Mike McFarland, a meteorologist with the Seattle branch of the National Weather Service, said the snow level will be at 6,500 feet on Saturday night. That means that much of the precipitation in the mountains will come as rain instead of slow.
McFarland expects to see between 1 and 3 inches of rain in the lowlands of King County, and up to 6 inches in the mountains.
The last severe flooding in the Snoqualmie Valley occurred in February. On the week of Feb. 7, floodwaters rose above 56 feet near Carnation for the fifth time during the flood season. October 2019 also saw a major flood that was unusually early. It hit farmers in mid-October, right before the Halloween weekend.