Yesterday was the 33rd anniversary of the Mt St Helens eruption. I was living in CO at the time and I remember that you could see a very fine coating of powder on the cars afterwards. There's a unique mtn biking experience with the Plains of Abraham and Smith Creek trails. The trail takes you right up through the blast zone with awesome views of the destroyed mountain side. If you're ever in the area you should give it try.
I never get tired of looking at footage of the eruption and landslide.
I was 3 and a half months old and living about 200 miles north when it went off. Obviously I don't remember anything about that day, but naturally there was a lot of local history covering it, especially in school, as I was growing up.
A couple interesting facts;
Thanks to the size and thickness of the ash cloud, much of Eastern Washington was blacker than the middle of the night with no moon or stars, in the middle of the day. Street lights and headlights were on a 2pm.
Ash from Mt St Helen's circumnavigated the globe, literally. It blew East, and kept going all the way around back to Washington.
One of the few people that refused to leave the mountain, and ultimately lost his life when his house was decimated from the landslide/resulting tidal wave out of Spirit Lake, was Harry Truman. Not the former President, they just shared the same name.