I climbed Mount St Helens 5 years after the blast. You never saw such desolation. Inch tall trees that would be buried by the wind, a few grasshoppers blown in by the wind, and some spiders.
I believe the blast was 1980, I climbed 3/4 the way circa 2001, it was still pretty young growth stuff, and booty-loads of downed trees. But very cool.