Good to see you too. I always appreciate your expertise!
I got way up close and personal when Mt. St. Helens blew in 1980. We were a couple hundred miles down wind and got 6" of talcum fine ash. It was very sulfurous and there were some respiratory problems. That stuff was incredibly abrasive but very much a net good for our soil (I was farming at the time).
This is a bit different smell from what I recall...
It was abrasive because it had volcano glass mixed in it. Very fine and deadly mix.... that stuff can essentially cut through the metal part of jet engines... if gets in :)
I saw lots of the damage, I am/was also a mechanic. We lost one pickup motor on a rig an employee HAD to drive to work. I've never seen anything like how those cylinder walls were polished. My original plan was to leave the bore alone and just knurl the pistons to take up the 0.003 overbore. But I couldn't hone the cylinders so I had to take the block to a machinist to have it bored 0.010 over and put in new pistons.
We actually heated some of the ash with a big torch and produced glass beads. Sort of pretty green color.