Late winter and early spring are landslide season in Western Washington. It’s not uncommon for heavy rain and melting snow to send sodden earth slumping down hillsides, blocking roads, covering railroad tracks and changing the course of streams.
Generally, the human response has been to deal with these problems as they occur. But two major disasters in the last 20 years point to the need for better advance planning, and a new report makes some key recommendations to consider.
The report by the SR 530 Landslide Commission was prompted by the March 22 landslide near Oso, in Snohomish County. At 10:37 a.m. on a wet Saturday, 10 million cubic yards of dirt and debris let go from a hillside that had been logged, smothering a square mile, including 49 homes, the state highway and the Stillaguamish River. It killed 43 people, some of whom were not located for weeks.
The Oso slide was a quick catastrophe, but another disastrous landslide played out over a period of months. It occurred less than 40 miles north of here, in the city of Kelso. In March 1998, neighbors in one of the city’s newer and nicer subdivisions, Aldercrest, noticed cracks in the foundations of their homes. Doors and windows suddenly stuck shut. Over the next year, the horror unfolded as the whole hillside crumbled. Ultimately, 137 homes were condemned and destroyed. Geologists determined that heavy rains had reactivated an ancient landslide, triggering the disaster.
The landslide commission’s new report would help predict, prevent and respond to these types of catastrophes. It makes 17 recommendations, including three priorities:
• Map more potential landslide hazard areas using aerial images.
• Improve funding and integration of emergency response teams.
• Clarify state laws surrounding mobilization of first responders to a disaster.
Less urgent recommendations include updating some laws requiring cities and counties to regulate land use in potentially hazardous areas.
Gov. Jay Inslee has included $36 million in his transportation budget proposal for landslide mitigation measures, funding for advanced imagery of the most slide-prone areas, and analysis of the data. With all of the pressure on the Legislature to spend billions on K-12 education, increased funding will be a tough sell, but the proposal deserves consideration.
Some fixes would seem to be less costly. The law could be clarified, for example, to allow state firefighters to respond to a disaster. At Oso, such help was denied based on the advice of an attorney for the state fire marshal’s office.
We share geology and climate with Kelso, and, to a lesser degree, with Oso. Experts say we aren’t in imminent danger of a massive event here, but landslides are a regular occurrence in Southwest Washington. In late 2012, a slide ripped away part of the foundation under Highway 501 in Ridgefield. A slide area hugs Lockwood Creek east of La Center. Areas along Washougal River Road are prone to slides, rocks and earth tumble onto railroad tracks in Felida, and the Columbia River Gorge has a long history of movement.
The forces of nature are powerful and unrelenting. Landslides will continue to occur, but Washingtonians would be well-served by paying more attention to understanding the threat, reducing the exposure and coordinating the response.
