Landslides and avalanches likely this week, Washington officials warn. What to know
Conditions are ripe for dangerous avalanches and there’s an increased threat of landslides across western Washington this week, the National Weather Service warns.
A landslide already struck a highway east of Leavenworth, Washington State Patrol Trooper John Bryant tweeted Monday afternoon. The debris slammed into a guardrail and blocked part of the eastbound lane of U.S. 2, according to WSP.
Heavy rain and snow fell around the Cascade Mountains and several surrounding areas “through early this week,” according to the Seattle office of the NWS. The amount of rain “increased soil moisture to high levels across western Washington,” resulting in “several minor mudslides … across the Olympic Peninsula.”
On Monday, the Washington State Department of Natural Resources issued a landslide advisory around the Puget Sound area and Olympic Peninsula, including Olympia, Tacoma and Seattle. More rain is “expected through early Wednesday with another 1 to 3 inches in the lowlands,” the NWS said.
“This amount of rain will put extra pressure on soil instability, leading to an increased threat of landslides,” the NWS reported Sunday. “Areas above 3000 feet in elevation will see some of the precipitation as snow and not be as affected.”
‘High danger’ for avalanches
The “US National Weather Service Seattle Washington” Facebook page posted Monday morning that there is “high avalanche danger for the Cascades through today.”
The “high danger” warning is red — behind only “extreme danger,” which is black — on the five-color North American Avalanche Danger Scale.
The Northwest Avalanche Center said in a Facebook posted that “an avalanche warning has been issued for the Cascades East Central Zone where triggering a slide is likely and will be big enough to bury or kill you.”
People are advised to “avoid travel in or below avalanche terrain,” and the NWS warned “travel in or below avalanche terrain is not recommended.
This story was originally published January 4, 2021 at 2:02 PM with the headline "Landslides and avalanches likely this week, Washington officials warn. What to know."