Winter Storm in East Slopes of the Washington Cascades, Washington

A trained spotter 4 miles east southeast of Roslyn, WA measured 12 inches of new snow in a 24 hour period ending at 1139 PST on Dec. 24th. Via a public report 30 miles west of Tieton, 0.25 inches ice accumulation from freezing rain was reported at 1000 PST on Dec. 24th. A trained spotter 25 miles southwest of South Cle Elum, WA measured 0.25 inches of ice accumulation from freezing rain at 1402 PST on Dec. 24th. Interstate 90 was closed between Dec. 23rd and the 24th due to heavy ice accumulations up to Snoqualmie Pass.

A series of surface frontal boundaries, warm air overrunning low level and valley cold pools, and a moderate transport of moisture in a west to southwest flow aloft resulted in impactful wintry conditions across southeast Washington, northeast and central Oregon. A mix of heavy freezing rain and heavy snow resulted in numerous traffic accidents and highway closures across the region during this period.