Work towards the very end of Spirit Lake Highway is set to start this week, restoring a key route to Mount St. Helens, three years after a landslide cut off access to the Johnston Ridge Observatory. 

The Washington State Department of Transportation says crews will start construction Wednesday to replace the Spirit Lake Outlet Bridge. 

The project comes after a massive landslide in May 2023 sent more than 300,000 cubic yards of debris onto the highway, destroying the original bridge and blocking the road. Officials say the new bridge will be longer and more durable, designed to handle the challenging conditions in the area while restoring a safe, reliable route for visitors.

Construction is expected to continue through fall 2026. After that, the U.S. Forest Service will begin repairs to the observatory before it can reopen in Spring of 2027.