One of our nieghbors was walking with several others in the lower community yesterday when it happened. It's almost more of a land slide then an avalanche. They said that the snow started moving then rapidly liquified into mud soup. Current working theory is that there was a lot of water moving under the snow pack which undermined the limited bond. That slope gets manicured from year to year so there aren't a lot of natural anchors to hold things in place.
The guy who owned the house that was totaled was apparently inside enjoying a cup of coffee when it happened. He's OK.
It's raining up here again.
The next week isn't looking good.
DOT Flickr page has some good images of what's going on up here...
http://www.flickr.com/photos/wsdot/3177744097/in/set-72157612242253091/