In addition to an occluded front's evening arrival in Washington, there were many factors that brought light to moderate snowfall to Eastern Washington and the Idaho Panhandle on Christmas night into December 26th. Significant precipitable water and a surface low's colder air provided conditions for snow and rain/snow mixes across the region. Only 1-2 inches fell in most low lands, but into the Spokane area and eastern North Cascade slopes up to 4-7 inches of snow was recorded.
The road conditions began to deteriorate when the started snow falling that evening, which led to a minimum of 33 crashes in the Spokane area. In addition to slippery roadways from snow, highway troopers responded crashes due to heavy, freezing fog slick roadways across eastern Washington.

Heavy Snow in EAST SLOPES NORTHERN CASCADES, WASHINGTON
From 25-DEC-20 10:00:00 to 26-DEC-20 04:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

A CO-OP observer station in Stehekin recorded 5.0 inches of new snow accumulation.

Heavy Snow in WENATCHEE AREA, WASHINGTON
From 25-DEC-20 16:00:00 to 25-DEC-20 23:50:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A member of the public, in east Wenatchee, reported an estimate 4.0 inches of new snow accumulation.

Heavy Snow in SPOKANE AREA, WASHINGTON
From 25-DEC-20 16:00:00 to 26-DEC-20 04:00:00 (PST-8)
Reported by: Broadcast Media

Local broadcast media, KREM 2, reported that Spokane police responded to an approximate 33 crashes in Spokane between December 25th evening and December 26th morning. The roads became slick with the snow coverage leading to numerous collisions.

Heavy Snow in SPOKANE AREA, WASHINGTON
From 25-DEC-20 16:00:00 to 26-DEC-20 04:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

The Spokane Metropolitan area received 3 to 5 inches of new snow accumulation. Local broadcast media reported that Spokane police responded to an approximate 33 crashes in Spokane starting December 25th evening into December 26th morning. The roads became slick with the snow coverage leading to numerous collisions.

Freezing Fog in UPPER COLUMBIA BASIN, WASHINGTON
From 25-DEC-20 22:00:00 to 26-DEC-20 06:00:00 (PST-8)
Reported by: Department of Highways

Heavy, freezing fog created slick roadways which led to rolling cars, collisions, and blocked roadways. Many occurred on US Highway 2 and Interstate 90. Washington State Highway troopers responded to 63 crashes overnight December 25th and the 26th. There are no reports of injuries or fatalities.

Heavy Snow in EAST SLOPES NORTHERN CASCADES, WASHINGTON
From 25-DEC-20 10:00:00 to 26-DEC-20 04:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

There were not many reports of heavy snowfall in the eastern Cascades. Most of the area received only a few inches of snow. However, two CO-OP observer stations, in Lucerne and Stehekin, recorded 5 to 7 inches of new snow accumulation overnight.

Heavy Snow in NORTHEAST MOUNTAINS, WASHINGTON
From 25-DEC-20 16:00:00 to 26-DEC-20 04:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

A NWS employee, via webcam at a snow board, estimated Mt. Spokane received 7.0 inches of new snow accumulation. The remainder of the northeastern Washington region only received a few inches of snow from this winter system. The heavier snowfall kept to the Spokane Metropolitan area.