That’s cool you heard the blast and went “WTH?”
I hiked Mt. St. Helens summer of ‘75 before the blast when I was working in Longview, WA. It was a gorgeous mountain. I remember getting severe altitude sickness driving on the south side of the mountain and only got a short hike in before quitting and having to get back to sea level. That was the only time that happened to me — severe, splitting headache.
That was a lot more ash around Cheney that CdA or Hayden. You figure that the ash fall drops off as the reciprocal of the square of the distance from the blast center.
“You figure that the ash fall drops off as the reciprocal of the square of the distance from the blast center.”
Given constant winds.
I was surprised that staying and skiing at high elevation in Colorado I did not get altitude sickness.