Rebuilding SR 504 and reconnecting visitors to Mount St. Helens

Permanent repairs begin three years after landslide destroyed Spirit Lake Outlet Bridge

TOUTLE - Three years after a landslide cut off access to the upper stretch of State Route 504, also known as Spirit Lake Memorial Highway, work is set to restore a key connection to one of Washington's most scenic destinations: Mount St. Helens.

Starting Wednesday, April 15, Washington State Department of Transportation contractor crews will begin work to permanently replace the SR 504 Spirit Lake Outlet Bridge and restore access to the Johnston Ridge Observatory in the Mount St. Helens National Volcanic Monument, east of Toutle.

"This is more than a bridge restoration project," said WSDOT Project Engineer Pedro Reyes. "It's about reconnecting people to Mount St. Helens. We're building a long-term solution that will fully restore safe access and ensure reliability for years to come."

What to expect

Crews will build a new two-lane roadway and bridge designed for the area's challenging terrain and changing conditions. The new bridge will be similar in width to the original structure, but longer and built to last.

What happened

Shortly after 9 p.m. on Mother's Day, May 14, 2023, more than 300,000 cubic yards of debris slid about 2,000 feet down a hillside above SR 504 near milepost 49. The slide buried the highway in rock, mud, ice and water and destroyed the 85-foot Spirit Lake Outlet Bridge.

Within two months, crews cleared the debris and built a temporary bypass road so vehicles stranded at Johnston Ridge Observatory could be recovered.

The unstable landscape and harsh winter weather conditions caused the temporary structure to fail after four months due to erosion, water flow and shifting ground.

To ensure safety, WSDOT removed the failed structure and materials until a permanent solution could be built.

Looking ahead

Work is expected to be complete in fall 2026. After construction, the U.S. Forest Service will begin work to restore Johnston Ridge Observatory, including power and other essential repairs, before it can reopen to the public. Once finished, travelers will again be able to drive the full length of SR 504 and visit the observatory to experience the dramatic landscape shaped by the 1980 eruption of Mount St. Helens.