Western Washington is experiencing “one of the greatest floods to ever strike” the region, with more heavy rain and additional atmospheric rivers expected into next week, according to local meteorologist Michael Snyder of Pacific Northwest Weather Watch.

In a video update posted Thursday morning, Dec. 11, Snyder said the ongoing atmospheric river has produced “absolutely ridiculous flooding” across the state, including record crests on multiple rivers and widespread landslides. He warned residents to avoid travel as saturated ground, swollen rivers and rapidly changing conditions continue to create hazards.

“You are witnessing history here across western Washington,” Snyder said.

Snyder described a weather pattern in which high pressure off California and a broad Pacific trough are channeling deep tropical moisture directly into the Northwest. The current system has already produced more than three inches of rain in Seattle and up to 15 inches in higher elevations over 72 hours, with Snoqualmie Pass, the Cascades and foothill communities seeing particularly intense runoff.

Many rivers are approaching or exceeding major flood stage, Snyder said, with some forecast to crest at or near record levels. He warned of “levy break potential,” rapidly rising water and conditions capable of producing “absolutely wild” impacts.

Snyder also noted numerous road closures, including I-90’s shutdown due to a landslide he said he narrowly missed by “20 or 30 minutes.” Logs and debris moving at high speed have caused injuries, he said, emphasizing the dangers of visiting rivers during flooding.

Another atmospheric river is expected to arrive Sunday and may linger into early next week, delivering additional heavy rain to an already saturated region. Snyder said a brief lull Friday might offer only temporary relief before more systems move in.

“Do not travel if you do not have to,” Snyder said, adding that landslide potential is rising across Seattle, Tacoma and foothill communities, while mountain snowpack continues to melt under unusually warm temperatures.

Longer range models suggest colder air may return late in December, potentially allowing mountain snow to rebuild after the warm storm cycle.

Here’s the latest video forecast from Snyder’s Pacific Northwest Weather Watch:

YouTube player

Detailed 7-Day Forecast

  • Thursday: Rain, mainly before 11am. Patchy fog. Steady temperature around 49. East wind 3 to 6 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible. 
  • Thursday Night: Rain likely, mainly before 7pm. Patchy fog. Otherwise, cloudy, with a low around 47. Calm wind. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible. 
  • Friday: A 40 percent chance of rain, mainly before 4pm. Cloudy, with a high near 55. South southwest wind 5 to 7 mph. 
  • Friday Night: A 20 percent chance of rain before 10pm. Mostly cloudy, with a low around 47. South wind around 7 mph. 
  • Saturday: Partly sunny, with a high near 55. South southeast wind around 6 mph. 
  • Saturday Night: Rain likely, mainly after 4am. Mostly cloudy, with a low around 48. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible. 
  • Sunday: Rain likely, mainly after 4pm. Mostly cloudy, with a high near 54. Chance of precipitation is 70%.
  • Sunday Night: Rain. Cloudy, with a low around 49.
  • Monday: Rain. Cloudy, with a high near 57.
  • Monday Night: Rain. Cloudy, with a low around 45.
  • Tuesday: Rain. Cloudy, with a high near 50.
  • Tuesday Night: Rain. Cloudy, with a low around 42.
  • Wednesday: Rain. Cloudy, with a high near 48.

Scott Schaefer

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