Yikes! Well, he was a geology major at the U of Oregon, with a minor in physics, so he should know better than anyone what the risks were. With 900 year intervals, only a third of which had gone by, I'm not going to worry too much.

Blew their snowmobiles up in the air? Holy Moly (or however it's spelled)!

Thanks, Chris, for your answers.

Cathryn