I was beginning to doubt my contact but it sounds like the 43 missing, added to the 17 bodies, may be what the sheriff they talked to was on about with his 50 or more figure. It certainly looks like that size of catastrophe to me.
Just the one stream above the Santa Ynez ranch did unbelievable damage, leaving 75% of the resort under mud, then pouring down through the Casa de Maria retreat which is totally destroyed onto El Bosque.
The Cold Springs creek was also devastating wiping out houses as it crossed E Valley Road. It has a basin to slow the flow higher up at E Mountain Drive, carved back in 1995/6, but it sounds like this was overwhelmed. Wondering what Riven Rock Road and Ashley look like.
I haven't figured the source creek for the Randall Road overflow yet but that took out 10 houses or so. I suspect it is the same creek that also went down El Bosque and split above it. Once it crossed E Valley Road it caused immense damage to Glenoaks and E Valley Lane, which is where the boulder field is extensive.
I suppose the boulder field gathers where the water slows or gets shallower.
http://www.huffingtonpost.com/entry/california-mudslides-death-toll_us_5a5625d3e4b0b117f881385f?ncid=inblnkushpmg00000009