Repairs expected to take at least a month; detour will remain in place until work is complete

Information released by WSDOT

Clean-up and repair work of series of rockslides blocking both lanes on State Route 20/North Cascades Highway near Rockport began this week, and will require the existing detour to remain in place until further notice. There are exceptions for emergency vehicles.

The work will clean up the highway east of SR 530, with travelers detouring around the slide area via SR 530 between Rockport and Marblemount. Emergency vehicles will be escorted onto SR 20 and allowed to use a bypass lane.

Interwest Construction contractor crews working for the Washington State Department of Transportation expect the work to take at least a month, depending on weather. Initial evaluations by geotechnical engineers show the slope above SR 20 is unstable and will require removing overhanging trees and rocks before reinforcing the slope with dowels to hold rock in place.

Funding for this project comes from Washington state’s preservation funds and is expected to cost around $700,000.

Detour route

During the closure, travelers are detouring via SR 530, Rockport Cascade Road and Cascade River Road.


The initial rockslide occurred the night of June 10, dumping about 150 cubic yards of debris onto both lanes of the highway. By morning, more rocks had fallen, and now crews estimate 1,000 cubic yards of debris – about 70 dump truck loads – will need to be removed.

Real-time traffic alerts will be posted to WSDOT’s regional Twitter account.


WSDOT keeps people, businesses and the economy moving by operating and improving the state’s transportation systems. To learn more about what we’re doing, go to for pictures, videos, news and blogs. Real time traffic information is available at or by dialing 511.