SR 20 - North Cascades Highway

Diablo Lake overlook

Diablo Lake overlook

Last Update: 4:36 p.m., June 12, 2020: Open

A signed detour is in place on State Route 20 North Cascades Highway between Rockport and Marblemount due to a rockslide at approximately milepost 99. The detour takes eastbound drivers from SR 20 to westbound SR 530 at Rockport, then east on Rockport Cascade Road, and west on Cascade River Road before returning to SR 20 in Marblemount. The same detour is available for westbound SR 20 drivers. There is no estimated time for a full road reopening. 

Seasonal snow clearing of SR 20 was completed on May 12. This route provides vital alternative access in this area that is critical in case of natural disaster, such as forest fires, and supports freight movement, particularly timber haul.

North Cascades National Park is open to travelers. As of June 12, the park reopened access to campgrounds, the wilderness information center, and Hozomeen (from the U.S. side, the border with Canada is still closed). It is important to note that many trails have not been cleared and visitor centers and group campsites are still closed. Please check with National Parks if you have more questions.

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.

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.

Reopening in the spring is usually accomplished by early May.

Winter recreation on SR 20
Hikers, skiers, snowmobilers and other recreationalists can access the closed portion of highway during the winter season. Users should park in designated parking areas to allow plow drivers the space they need to clear snow around the closed stretch’s access gates.

WSDOT closes this stretch of highway due to avalanche risk, so anyone using this area should check forecasts and be aware of quickly changing conditions in the mountains. Travelers can also check conditions with North Cascades National Park before trips to this area.

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 along 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/fall when the pass reports are suspended, you can find weather information with these links:


SR 20 North Cascades Highway Hotline

Lauren Loebsack, Communications
North Central Region-Wenatchee

DiAngelea Millar, Communications
Northwest Region-Burlington

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