A “significant” mudslide that covered a portion of Highland Park Way SW in West Seattle Wednesday morning may be out of the ordinary, but when you look at the rainfall data for February, it is less surprising.
Rainfall of up to 5 inches in the Puget Sound region last week increased soil moisture and the risk of landslides.
The added rainfall this week added to that risk.
“This amount of rain will put extra pressure on soil instability,” the National Weather Service wrote in a Special Weather Statement Tuesday afternoon, “leading to an increased threat of landslides.”
It turns out the Weather Service was right.
Around 5:20 a.m. on Wednesday, a saturated hillside gave way in West Seattle’s Delridge neighborhood. The slide, between SW Holden and West Marginal Way is blocking Highland Park Way and has reported cut power to nearby buildings, KIRO 7 reports. About 2,000 Seattle City Light customers were without power at the peak of the outage.
— Rebecca Perry (@Rebecca_Perry) February 15, 2017
“There is tons of mud and debris on the road, about 3 to 5 feet deep, that crews will need to clean up,” KIRO 7 reports.
The USGS reports the area is ripe for mudslides and landslides. Based on current data, the Tacoma Narrows, Sea-Tac, and Seattle/Boeing Field are all at elevated risk. Precipitation totals have exceed the predetermined threshold, as shown in this graph:
It isn’t over yet
The last several days of February have been wet, and things may only get wetter.
The National Weather Service reported that, by Wednesday afternoon, Seattle will be in the top 10 of the wettest February months.
“By the end of the day, we could reach 7th,” the Weather Service tweeted. “And it’s only Feb. 15th.”
KIRO 7 Meteorologist Nick Allard says rain is possible through Thursday, with a few showers on Friday. Light rain/scattered showers are possible for the weekend.
In defense of meteorologists: Don’t get mad at forecasts