The cloud of ash reached Missoula, Montana (~400 miles downwind) by late that afternoon. It turned dark earlier than usual that evening, like a storm was comong. We got about 2 inches of ash in all by the next morning and were locked in our apartment for 4 days before a rain-storm finally turned the fluffy stuff into concrete.
It shut the town down because they said NOT to use your car as the ash was fine particles of volcanic glass which would get through the filters and erode the pistons and rings.
It was a mess downwind for a long time. I went to college in Eastern WA in 1986, and ash was still everywhere... would blow around when it was dry, and just turn to paste when it was wet. You can still see it now in undisturbed areas... it just doesn't soak in.
I was in 8th grade I guess... and I remember seeing a few of the minor eruptions from our boat on Puget Sound.
I think I was in Yard Birds Market in Olympia with my dad on May 18. I remember listening to the radio in the sporting good dept with the store clerk.