Landslide Information and Updates

Landslide on Highway 504 near Johnston Ridge Observatory


Operations at Mount St. Helens Institute and the Science and Learning Center have not been impacted by the landslide. Summit Climbs, Glacier Overlook Hikes, youth programs, events and camps are still happening. The landslide poses NO DANGER to our operations or facilities. The roads to the Science and Learning Center and the south side of Mount St. Helens remain open and clear. Coldwater Lake, the Hummocks Trail and other nearby trails are currently closed due to a lack of bathroom facilities but are expected to open in the near future. 

Recreation opportunities remain largely unimpacted by the landslide. It occurred on a small section of Highway 504 near Johnston Ridge Observatory, blocking the way to visit that particular area. 

We are working with our partners at the USFS and Discover Your Northwest to get things up and running. We will continue to update this page with new information as it comes in. If you have specific questions please reach out to

What Happened? 

On Sunday evening, May 14, 2023, around 9 p.m. a saturated deposit of material from the 1980 volcanic eruption of Mount St. Helens gave rise to a gravity-driven debris flow that released thousands of tons of debris into South Coldwater Creek. The debris flow, referred to as the South Coldwater Slide, caused significant damage to the upper portion of State Route (SR) 504 near milepost 49 leading up to the Johnston Ridge Observatory north of Mount St. Helens. The event followed a recent warming trend and significant snowmelt that had saturated the ground. The debris flow washed out the Spirit Lake Outlet Bridge, an 85-foot structure, damaged the roadway, and severed power to Johnston Ridge Observatory.

Links and Resources

South Coldwater Slide Frequently Asked Questions are attached for reference.  They are also available online: South Coldwater Slide Frequently Asked Questions   

A map has also been added to the website: South Coldwater Slide Closure and Vicinity Map (PDF)

Gifford Pinchot National Forest Information 


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Washington State Department of Transportation Information 


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