I remember washing volcanic ash off of my Dodge Dart in Fort Collins, CO. The fine grained particulates went further than that. The dust eventually circled the planet.
Mount St. Helens is still considered the most active volcano in the vast Cascade Range. It's an occasional puffer. There's a new dome building inside of the maw that the blast left behind. After thirty-six years, green things are returning. Animals are calling it home too. Remember, Mother Nature detests a void.
In 1982, President Reagan set aside 110,000 acres as an National Monument. I've seen the steady comeback in 1986, 2012 and a few days ago. It's progressing along on a scale humans can notice. That's fast.
The Monument is a laboratory of what nature can do if left to its own devices. Humans would only hinder the inevitable. One day (not in our lifetime) there will be an old growth forest here. That is, unless Mount Saint Helens decides to blow it's cool again.
You better check it out.
Jeff from Newport, Oregon