Monday, November 21, 2011

Washington's North Cascades Highway Closed for the Season

The American Alpine Institute just received the following note from the Washington State Department of Transportation:

OKANOGAN – The gates are closed until spring on the North Cascades Highway. SR 20 was closed temporarily at 8 p.m. Tuesday, Nov. 15, in advance of heavy snow storms. When conditions and forecasts were reassessed early Monday morning, Nov. 21, maintenance and avalanche teams determined it wasn’t safe to attempt reopening the highway for Thanksgiving.

8” of new snow accumulated by noon today and the forecast calls for 4” more by this evening, 9” more overnight and as many as 16” Tuesday. Coupled with warming temperatures, those quickly-filling avalanche chutes won’t remain stable and it’s unsafe for either our crews or motorists to be under them.

Last year, the highway closed temporarily on Nov. 29 and two days later after a storm dropped 2’ of new snow, it closed until spring on Dec. 1. The 37-mile winter closure zone begins seven miles east of Diablo Dam at milepost 134 on the west side of Rainy Pass (elevation 4,855 feet) to nine miles west of Mazama at milepost 171 below Washington Pass (elevation 5,477 feet).

Last spring, the highway reopened May 23, marking the second latest in the highway’s 39-year history. SR 20 typically reopens between the last week in March and the first week in May. The earliest opening ever was March 10, 2005. In 1976, a drought year, it remained open all winter.

Visit the North Cascades web page: and the North Cascades Flickr - photo site: 

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