When I was a kid I remember this happening. I was 4 years old in 1980. But I remember images of the ash, the eruption, cars in ditches, bridged destroyed and first hand stories of watching the eruption happen in the rear view mirror of a car. 

Mount Saint Helens eruption aerial photo

This image is incredible if you think about how sketchy it must have been to be in aircraft so close to an eruption.

-M

Source vulcan.wr.usgs.gov