when Mt. St. Helens erupted, it deposited ash in montana, hundreds of miles away.In Idaho it was several inches deep on the ground, and caused
some plants to wither and die.

some enterprising folks packaged and sold samples of it to commemorate the event. I especially remember small vials of it and blown glass containers of it going for souveniers. at least one of the people who died in the eruption was warned to leave but stubbornly insisted on staying.