North Cascades Highway closing for the winter

In a sure sign that winter is on the way, the North Cascades Highway is closing for the season Thursday night.

The North Cascades Highway, also called State Route 20, will close at 6 p.m. from the Ross Dam Trailhead, milepost 134, and Silver Star Gate, milepost 171.

More news: Snow on the way to Washington mountains

This is the second latest closure of the highway in the last 10 years.

A winter weather system will arrive Thursday, bringing rain to the Western Washington lowlands and a few inches of fresh snow to the mountains above 2,000 feet. Then, more potent weather systems are expected to track onshore, with rain in the lowlands and as much as one to two feet of new snow in the mountains.

“The stretch of SR 20 that crosses Rainy and Washington passes also crosses dozens of avalanche paths between Whistler Mountain and Delany Ridge,” the Washington State Department of Transportation (WSDOT) said in their seasonal update. “Staffing, funding and proximity to the national park make it not feasible to do ongoing avalanche control through the winter in the North Cascades.”

SR-20 is the state’s longest highway, running 436 miles. It crosses Washington Pass at 5,477 feet and Rainy Pass at 4,875 feet in the North Cascades. It begins at US 101 at Discovery Bay on the Olympic Peninsula to US 2 near the Idaho state border in Newport. Rainy Pass is about four miles to the west of Washington Pass.

The North Cascades Highway east of Washington Pass has the distinction of being among the top areas in the United States for most avalanche paths per mile of highway.

The highway will be reopened in the spring when road crews are able to clear the road.