First, a huge thanks to Mike Huggins for all his help with this post.

Last Monday, a large rockslide closed Route 4 in Washington County in New York State.  The landslide consisted primarily of large blocks of late Precambrian metamorphic rock.  PostStar.com has a good image gallery of the landslide:

http://poststar.com/news/local/rock-slide-closes-route-in-fort-ann/article_132e96ee-16cb-11e2-ae07-001a4bcf887a.html

Although the landslide occurred at just after 9 am, no-one was buried or hit by the landslide.  Inevitably, clear up took a few days – this article details the challenges that they faced.  There is also a video of the site on this site (once you get past the Christmas advert), although it is unclear to me as to why this was “an accident waiting to happen as indicated by the report”.

It would be interesting to analyse the stability of this slope.  The failure has clearly been controlled by existing joints in the rock mass.