Heavy Snow — East Slopes of the Washington Cascades, Washington

2022-01-05 to 2022-01-07 · East Slopes of the Washington Cascades, Washington

Event narrative

The Co-op observer at the Easton Dam in NW Easton measured 27 inches of new snow in a 24 hour period ending at 0800 PST on Jan. 6th. The Cocorahs observer WA-KT-7 8.9 miles E of Cle Elum, WA measured 18.5 inches of new snow at 0700 PST on Jan. 6th.

Wider weather episode

A prolonged period of northwest flow over the Pacific Northwest guided several rounds of moisture advection across the mountain zones, leading to upslope moderate to heavy snow showers nearly each day. Meanwhile, surface frontal systems and a series of shortwave troughs in the flow aloft produced moderate to heavy snow as well as some periods of freezing rain across the lower elevations. Strong winds were also produced as a result of these shortwave troughs and surface frontal systems at the beginning and end of the prolonged winter weather conditions. During this extended period of winter weather, the I-84 and several state and US highways in Oregon and Washington closed for extended periods of time due to increased traffic accidents from ice and/or moderate to heavy snow accumulations on roadways.

Source: NOAA Storm Events Database, event_id 1005200. Narrative written by the NWS forecast office that issued the report.