Last Saturday a hillside gave way in rural Washington, creating a mile-wide wall of mud which buried a small neighborhood. The shocking fact is not that the mudslide occurred, but that the neighborhood existed there in the first place.
This is not the first mudslide in the area, which back in the 1960s was known as “slide hill”. The last one, in 2006, also stopped the river and was probably (geoglogically speaking) a precipitating cause of the most recent slide – when the river re-cut its channel, it began to further erode the section of hillside which was supporting the loose soil that gave way this week. As the Seattle Times reports:
John Pennington, head of Snohomish County’s Department of Emergency Management, said at a news conference Monday. “It was considered very safe,” Pennington said. “This was a completely unforeseen slide. This came out of nowhere.”
What is astounding is that Pennington seems to have no knowledge of (or is ignoring – but I choose to give him the benefit of the doubt) the Army Corps of Engineers report issued in 1999 which predicted both catastrophic mudslides. Also ignorant is Snohomish County Director of Public Works Steve Thomsen, who said there had been no way to predict the slide.
The 2006 slide took place in winter, on Jan. 25. Three days later, as the new channel cut the land, “residents and agency staff reported the eerie sound of trees constantly snapping as the river pushed them over,” wrote the Stillaguamish Tribe’s Natural Resource Department on its website. But the sound of construction competed with the sound of snapping trees.
“They didn’t even stop pounding nails,” said Tracy Drury, an environmental engineer and applied geomorphologist who assessed the area with Miller soon after the landslide. “We were surprised.”
At least five homes were built in 2006 on Steelhead Drive, according to Snohomish County records. The houses were granted “flood hazard permits” that required them to be jacked up 1 to 2 feet above “base flood elevation,” according to county building-permit records. Another home was built in the neighborhood in 2009.
As ironic as it might be, the flood hazard permits indicate that at least one hazard system was working well enough to note that there might be flooding. But what was in place to control for the fact that the entire hillside was ready to fail? That should have been the job of the planning department – which approved continued housebuilding even after the 2006 slide and didn’t stop any of the building that was already going on. If the planning department had done their job, if the county officials had actually bothered to stop and consider the risks of putting people’s homes in this area, this mudslide wouldn’t be a disaster. This is exactly the same thinking that leads to further development on floodplains, that leads a University to spent millions of dollars on an athletic facility which sits on an earthquake fault (LINK), that throws money at natural hazards instead of getting out of their way. So much emergency planning doesn’t occur in emergency planning offices (although Pennington’s ignorance is inexcusable), but occurs with the Army Corps of Engineers and in that most mundane of realms – the County Planning Office. That’s where catastrophes are prevented. Or where they are allowed to occur.