Mt St Helens Questions!!?

The eruption was VERY explosive, and it moved everyone in the area OUT of the area, IF they could still get out in time. It killed a few as well. Your two more "scientific" questions are beyond my memory, although the History Channel, as much as I find them disgusting liars, did have a good program on it, but I can't ever tell when the program's on, so, . . ., sorry. God Bless you.