St. Helens and the other many active and dormant volcanoes are all part of the Pacific Ring of fire, and the entire area in the Pacific Northwest is very geologically active. We also have the Cascadia fault in close proximity, and it’s an open question out here about which one will set off the other...
The real threat to the area is Mt. Ranier, because if it ever does a St. Helens, the eruption and pyroclastic flows would flush the Puget Sound like a giant toilet, and scour out everything between the volcano and the sea.
Don’t tell me that. Our “survival cabin” is in Elbe at the foot of Mt. Ranier. If the southern border of AZ breaches, that’s where we are headed.