Washington State's Mudslide Area Has Long Been a Problem

The pocket of Snohomish County hit by a mudslide Saturday has long been susceptible to slides and floods, bedeviling engineers who for decades have built dikes, rock buttresses and drainage systems in hopes of managing the river and stabilizing the hills.

 

For the North Fork of the Stillaguamish River — clean and clear in the early 1900s, when it became known as an ideal steelhead stream and was fished by the likes of Western novelist Zane Grey — there was the flood of 1933, the slide of 1967, the slide of 2006.

The slide eight years ago dispatched a wall of mud down the same hill that buckled this weekend. “This is the very same mass of rock and dirt,” said Tim Walsh, geologic hazards chief for the state Department of Natural Resources. “It just moved again.”

“Landslides often occur in the same place over and over.”

The Stillaguamish, no longer so clean and clear, has changed paths repeatedly while the wet hills have loomed as a constant threat to homeowners and to drivers on Highway 530.