Posting has been a bit limited of late due to field work and deadlines.
I visited a large slide area on Hood Canal recently. I had been to the same slide area a few years ago before it reactivated and identified a clay unit that is rather consistently associated with a number of deep-seated landslides in the area. With the more recent movement it really doesn't take a geologist to know something is amiss. Lots of obvious and not so obvious hints.
Silt/clay unit that is unraveling and is the cause of the failure