I've noted before that I try to keep this blog pretty focused - on beaches. Or maybe shorelines in general. Or maybe on geology. This is mainly in that last category, although there's not actually much geology in this post.
We were in New Mexico last year when I heard someone ahead of me in line ask the clerk if they'd heard about the big landslide up in Washington. Some quick work on the internet confirmed where it was. I guess I had heard other geologists mention the "Hazel" slide after the 2006 event, but knew little more about it than that. The field trip at last week's AEG workshop on landslides was my first chance to visit the slide and it was great to be able to do it in the company of people who know a lot about geology and landslides.
The Oso landslide occurred on March 22, 2014, on a Saturday morning when pretty much everyone in Steelhead Haven was at home. The hillside collapsed - on the site of an old, recurring slide - and ran out across the entire valley floor. Subsequently, geologists have begun to uncover evidence that this section of the North Fork of the Stillaguamish River has seen this kind of event before - although like earthquakes, they do not occur often and there is probably little way to predict just when and where they'll occur. And when they're not occurring, these are very attractive places to live.
Engineers and lawyers and government agencies will be debating the details for years, but I guess my takeaway was that the more we know the better, but that we can never know everything as well as we might want. Especially in hindsight. High bluffs and barrier beaches and floodplains are created and maintained by natural disasters. That doesn't mean we can't build on them, but maybe as a society we have to do more to educate ourselves about the risks.
Two miles downstream, you wouldn't know what happened less than a year ago.