Washington State Department of Transportation (WSDOT) crews began clearing the North Cascades Scenic Highway of snow from the west side this week, and will start working from the east side — in the Methow Valley — on April 9.
The dates were selected after WSDOT staff assessed conditions on the snowed-in road last week, the agency said in a press release.
West-side crews started at Diablo on Monday (March 26). East-side crews will start at the Silver Star Gate west of Mazama on April 9, WSDOT said.
Last year, the snow-clearing work started April 10 and the highway’s reopening wasn’t until May 16, well past the fishing season opener and Winthrop’s ’49er Days festival (the annual celebration will be May 11 – 13 this year).
In 2016, the pass opened on April 22. An early opening isn’t likely this year, WSDOT said.
Once the clearing work begins, the highway will be closed to recreationists Monday through Thursday. The highway will be accessible Friday, Saturday and Sunday for snowshoeing, skiing, snowmobiling and even bicycling beyond the gates, WSDOT said.
Snow-clearance work from the east will begin later than from the west because full avalanche chutes make the highway below too hazardous, WSDOT said. Warming temperatures over the next two weeks are expected to cause natural slides, clearing many chutes.
Last week, the North Central Region Avalanche Crew and Area 3 Twisp Maintenance Management assessed the condition of the road and the avalanche potential from Silver Star gate to Rainy Pass. “Depth measurements were taken, snow caves were dug to evaluate the stability of the layers of snow in the chutes, temperatures taken and a great number of observations recorded,” WSDOT said in its press release.
“The actual starting date target is the result of the assessment coupled with forecasts for the days and weeks ahead, equipment and staff availability and contractors,” WSDOT said. For that reason, predicting a reopening date is difficult.
Snow on the road is only part of the picture, WSDOT said. Many of the depth measurements below avalanche chutes were on par with or less than an average year, but some of the chutes had released snow and their depth far exceeded the norm, according to WSDOT.
For example: Cutthroat Ridge No. 4 had 10 feet this year, but only 5 last year. Cutthroat Ridge No. 6, on the other hand, had 13 feet this year compared to 25 feet measured during last year’s assessment. Liberty Bell No. 3 had 50 feet this year and 35 feet last year, while Liberty Bell No. 1 only had 20 feet of snow below it on the road this year, compared to last year’s 45 feet, WSDOT said.
WSDOT’s assessment revealed that here’s a persistent weak layer in the snow higher up in the chutes in zones from Cutthroat to the Beebe and Ruby zones west of Rainy Pass.
The highway was closed for the winter last Nov. 10.