A large debris flow on Sunday, May 14, at state Route 504 covered the highway at milepost 49 with rock, mud, ice and water.
The slide caused significant damage to the Spirit Lake Outlet Bridge and highway, effectively blocking access to Johnston Ridge Observatory on the north side of the Mount St. Helens National Volcanic Monument.
The following day, geotechnical engineers determined the slide area was unstable and posed potential safety concerns. Out of an abundance of caution, according to a news release this week, the highway was closed at milepost 43 and remained closed until further notice.
On Saturday, June 17, access to Coldwater Lake and the Hummocks Trail is set to be restored. The Mount St. Helens Science and Learning Center at Coldwater is also open to the public every day from 10 a.m. to 4 p.m. and, in other news from this week, USGS has successfully restored a water sensor that was damaged by the slide.
“Local agencies are working together to address the impacts of the slide and reopen the highway to visitors,” the news release stated.
Those visiting the volcanic monument on Saturday should be aware, the annual Tour De Blast bike ride will be taking place. Drivers should remember to slow down, move over and drive carefully when cyclists are present, the release stated.
For more information, head to www.fs.usda.gov/giffordpinchot.
