That is ash blowing across the train tracks about three or four days after Shinmoedake erupted. I can’t remember if they still had the rail lines closed off or not, but highway traffic was shut down for a week.
Ash falls, piles up, and drifts like snow. But it blows around quite easily and the slightest breeze will pick it up and put it in your eyes. The real danger is it getting into your lungs. The ubiquitous surgical masks everyone in Japan wears like a veil of shame do help slightly, but I was still out of comission for two weeks afterwards because I was hacking a lung up. The doctor claimed it was a virus, and perhaps it was. My body was spending too much of it’s resources trying to clear me out to fight one.
Three years later you could still see piles of ash in corners around parking lots or in drains.