"It is quite possible since we will be dogsledding on the Boundary Waters for ten days that the 400 pound sled might fall through,” Brad, our grizzled Outward Bound instructor told us matter-of-factly. “We need to practice an ice rescue while we are at base camp and we can warm people up in the sauna afterwards.” He glanced over the fifteen of us college students warily.  “I need two volunteers to jump into the ice so that we can practice a rescue.”