Seattle, WA, United States (4E) – A slow-moving storm will bring downpours and thunderstorms that will trigger flashfloods in the Northwest and front range of the Rockies while slightly affecting northern Idaho and western Montana from Thursday afternoon to evening.
The Northwest thunderstorms, the strongest of which will unleash damaging winds and hail, will affect Spokane, Washington; Boise and Idaho Falls, Idaho; Casper, Wyoming; and Denver, according to Accuweather.com and the Storm Prediction Center.
Flash flood risk across the Northwest will persist while spotty storms will affect the Rockies until Friday.
On Wednesday morning, some areas of Western Washington received more than a month’s worth of rain causing flash floods in some areas that experienced a long dry spell. Sea-Tac Airport received 1.07 inches of rain, more than the average monthly rainfall for August for the area, from midnight to 6 a.m. Wednesday.
On Tuesday, a 7-hour, 180-mile-long sandstorm in eastern Washington downed trees and power lines, and contributed to a multi-car accident. An east-west line of thunderstorms moving north out of northeast Oregon just before 3 p.m. PDT Tuesday kicked up the wall of dust, Weather.com reported.
Visibility became near zero in parts of Adams and Whitman counties because of the dust leading to the crash on Interstate 90 west of Ritzville, Washington that injured five people.
After the sandstorm, wind gusts downed trees in Moscow, Idaho cutting power to 5,800 homes. Power lines were downed in Spokane, Washington leading to 10,000 homes without electricity.