I'm guessing that the angle, surface type, and speed of travel of the glacier are elements that affect what happens within glaciers. Pretty interesting stuff! Mt. Rainier is made entirely of mud, so I'm sure that plays a role.

There were a couple of things about Zack's situation that contributed to his disappearance. First, he wasn't supposed to be climbing on glaciers. Second, he didn't have any previous ice-climbing experience. And third, people don't generally climb on that side of Mt. Rainier. It's still a little crazy-making, though.

I think we all would have had a slightly easier time coping with the situation if he'd been willing to learn how to PROPERLY climb before attempting shenanigans. But young men are hard to stop when they're hellbent on taking risks.