Thank you all for the discussion and intelligent threads. Curiosity is alive and well. To follow up on the crystalline snow thread, it seems possible that the tent stove, the ambient temperature or an aerial incindiary would be a heat source. I dislike the stove for the reason that the tent interior roof would be scorched. A change in ambient temp is certainly possible, even likely. I struggle with the observation that the tent fly was buried so deeply in rough snow. Rough, not winddrift snow.
If I were in that situation and I experienced a distant flash and blast, I'd hunker down and wait. If I wait, I have enough time to put on a coat or boots. If that same detonation were very near me blowing chunks of snowy debris hitting the tent, I'd fear that the next blast would be in my lap. I would cut and run!
I understand that snow chunks on a pitched tent would fall off. Later, when the tent buckled under the weight of snow much renained. The material on the collapsed tent was partially cleared off by the rescuers. It seems that the sheer quantity of blocky snow surrounding the tent, if thrown off by the rescuers would necessitate them stomping all over the top of the collapsed tent, yes? Please advise. I still find reason to believe their collective misfortune came from the sky, delivered my a man made delivery system.