Nearly two feet of new snow and several snowslides, coupled with a weather forecast calling for more snow through the Thanksgiving weekend, prompted the Washington State Department of Transportation to permanently close the cross-state highway today, Nov. 20.
Crews temporarily closed the highway at noon Monday, Nov. 19, when snow began falling at the rate of more than two inches per hour, causing three snowslides.
“By this morning, we had 19 to 20 inches of new, heavy, wet snow,” said Twisp maintenance supervisor Don Becker. “That brings the total on the shoulders of the highway to 38 to 42 inches, and it only takes 2 to 3 feet of snow to fill up the avalanche chutes.”
Slides below the Liberty Bell avalanche chutes, just east of Washington Pass, dumped snow on the highway – the largest was 14 feet deep and 50 feet wide. Below the passes, heavy rain caused mud, rocks and trees to spill across the road.
“It’s just not safe for our crews or the public to be up on the highway,” Becker said.
Last year, the highway closed temporarily on Nov. 15 and for the season on Nov. 21. 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 10. The State Route 20 North Cascades Highway typically reopens between the last week in March and the first week in May. The earliest opening was March 10, 2005. In 1976, a drought year, it remained open all winter.
Visit the North Cascades web page:http:// www.wsdot.wa.gov/traffic/passes/northcascades.