SR 20 - North Cascades Highway

Diablo Lake overlook

Diablo Lake overlook

State Route 20 is the northernmost route across the Cascade Mountain Range in Washington and is commonly referred to as the North Cascades Highway. This scenic byway offers travelers a wide array of beautiful vistas and is part of the Cascade Loop , a 400-mile driving tour through the Cascades. 

2018 Winter closing - 4 p.m. Wednesday, Nov. 28.

Avalanche chutes fill up, SR 20 North Cascades Highway closes for the season

2018 Spring opening - May 11.

The North Cascades Highway reopened Friday, May 11 at 10 a.m.

View the Flickr album

Why we close the highway in winter
We close the North Cascades when weather, snow conditions and avalanche danger threaten the safety of drivers and our maintenance crews. Avalanches typically close the highway between late November and mid December. We close the highway on the west side at milepost 134, east of Diablo, and on the east side at milepost 171, 14 miles west of Mazama. As the snow gets too deep for the plow truck, the east closure point is moved 7 miles down to the Early Winters Information Center at milepost 178.

Reopening in the spring is usually accomplished by early May.

Current driving conditions
November 1 until it closes (usually around Thanksgiving) and when it reopens, we post the current North Cascades Pass conditions on our WSDOT mountain passes Web page as we do for all of the passes. May (spring) through October (fall), pass conditions are only posted if there's a potential travel hazard.

Avalanche areas
The North Cascades Highway closure zone has 27 avalanche chutes, some stretching more than 2,000 feet above the highway.  By way of comparison, avalanche chutes at Stevens and Snoqualmie Passes are all well under 1,000 feet high.

View a detailed avalanche area map on Flickr

Web cameras

Current weather conditions
For recreation purposes and while the highway is closed, or in the summer when the pass reports are suspended, you can find weather information with these links:


SR 20 North Cascades Highway Hotline

Jeff Adamson, Communications
North Central Region-Wenatchee

Andrea E. Petrich, Communications
Northwest Region-Burlington

Sign up for spring reopening email updates for the North Cascades Highway