Most recent Clay Bank Landslide event on the Nooksack River
One of the big lessons from the Hazel/Oso Landslide was taken up by John Stark and Ralph Schwartz with the Bellingham Herald. They did an early article shortly after the Hazel/Oso Landslide regarding the landslide hazard in Whatcom County, Washington State (Whatcom County Has Its Share of Hazardous Slide Areas, Too). Whatcom County is two counties north of Snohomish County where the Hazel/Oso Landslide took place. And like Snohomish County has valleys that extend into the Northwest Cascades and North Cascades.
John and Ralph did a very good job with the subject. They spoke with a few local geologists and Roland Middleton with County Public Works. Roland has been the County a long time and was formerly in the Planning Department. John and Ralph also have their own news archives to go through assembling past landslide events in Whatcom County (old news stories archives are an important landslide hazard resource).
There are and will be some very hard painful lessons associated with this horrible event. But one lesson should be for local communities to take a hard look at their own risks from landslides and perhaps other natural hazards and assess how those hazards are being approached. Hence, the story angle John and Ralph went with is very important and should be an angle local reports should take not just in Washington State but in any area with landslide potential. And news stories should be followed with a hard look at how these hazards are being approached by local government. What are the regulations? Are the landslides or other natural hazard areas identified? What are the public awareness programs? If people live in a hazardous area, What is being done to reduce that Hazard?
6 comments:
Dan, you have another very timely post here. Your final lines in your post are my thoughts exactly. In my Natural Disasters classes I like to emphasize that after a disaster there is a "two year window of opportunity." The meaning is that after a harmful natural event, even a catastrophe, society has about two years to make changes before we forget how horrible the event was and lose motivation to make policy changes that could reduce the effects of future similar events. A large part of lessening the probability that natural processes become natural disasters involves wise land use, and not wise in a business sense but in a geologic sense. Too many people without geologic knowledge assume that one patch of ground is as good as another when it comes to building homes. Price, comfort, and convenience seem all too often the ONLY factors that figure in decisions about where to live or build anything.
My perspective is that it is the duty of the State and local (county, city) governments to inform people of geologic hazards; and in a case like Oso, building permits should have been denied, land sales should have been denied, people should have been moved out of the area or fully informed of the danger if they opt to stay on. However, I don't think the latter option should even be on the table. Enough has been known about the Oso area that no one should have died here. Another option would have been for the state to instrument the hillslopes such that remote readings could be sent and alarms sounded when conditions reached a critical stage, forcing evacuations and closing the road.\
Fred Becker, LG, LEG
After every fire in the WUI, there are cries to prevent people from ever building there again. After every flood, there are cries to prevent building in the 50/100/500 year flood plain, and so on. The simple fact of the matter is that property law, local governments, and risk assessments seldom get on the same page. It's a political decision, and it will be hard. But something needs to happen, and it usually takes a tragedy to make things happen, for a while.
Dan, you're doing a great job of providing images and analysis, which is what a lot of people are looking for right now. I appreciate your posts!
While I agree with those who say that the state and county have an obligation to protect their citizens, and to limit construction in hazard areas, I think this points out a fundamental weakness in the way we evaluate and map those hazards.
Simply put, Steelhead Drive, and all the homes on it, were not in a hazard area. Not because there wasn't a hazard (obviously), but because it wasn't mapped. The geologic hazard area maps from DNR, from Snohomish county, and from every other county I've ever seen identify unstable and oversteepened slopes as hazards, and they restrict construction in those zones. NONE of them map a downslope area as a hazard. The areas where the debris will flow are not identified. So, the average homeowner who consults the hazard maps won't realize they're building in a dangerous area. Nor will the average clerk in the building or planning office. All they see is that the lot/street/home/etc. is outside the shaded hazard area, so it must be safe. They don't know that the maps only tell half of the story.
I know that mapping likely debris flow channels and fans will require a lot of additional study, but if we want the hazard maps to represent the true hazards, those areas need to be shown.
Scott: Your comment acurately reflects a common problem regarding how landslide hazards trigger a geology hazard review at the local government level. There are a few local governments that include run out distances within hazard zones. But even those ofetn underestimate the potential hazard. And in an odd reverese they may overestimate the risk within areas above the landslide hazard area; that is set larger setbacks from the top of slope than at the base. Then there is the problem of what to do after a hazard is recognized after homes have already been built.
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