TomTerrific
Well-Known Member
http://myscienceacademy.org/2014/02/16/have-you-ever-seen-half-of-the-mountain-disappear-watch-this-video/
She blows about 1:15 in. It wouldn't surprise me if some of the photographers did not survive. I know there was film found showing non-survivable conditions.
The article gets a couple of things wrong, but overall it is good.
Wiki has some very good graphics: http://en.wikipedia.org/wiki/Mt._St._Helens_eruption
Note the avalanche immediately before the eruption.