I heard a distant rumble, and turned my head to see a gigantic chunk of ice cascading thousands of feet down the side of the mountain. The ice had broken-off the edge of a glacier near the summit dome. Obviously, the area below these ice cliffs is one of the more hazardous places to be on Mt. Rainier. I had to wonder about the wisdom of people who climbed routes through this zone - no amount of equipment or experience could save you from this kind of event. It's probably smartest not to take that kind of risk.