and that's what creates this massive debris field and explosion. >> david, in terms of a debris field like this on a mountain slope, it's got to be incredibly difficult to work this kind of a crash site. >> it's very similar to an air crash i worked up in casper wyoming, and it was snowing then. we had snow. we had debris. we had everything on the ground. we couldn't actually find the accident. we found a spot where we suspected it had hit. i was dropped off in a helicopter because there was no place to land. search and rescue in snow cats. they don't have that advantage here. they can't take snow cats or snowmobiles up to the area because it's already difficult to get to. that night in casper, because of that terrain an investigating we were able to find it in the snow but the helicopters couldn't come back to get us, and the search and rescue team we stayed there the night to