In 1959, ten people went on a skiing expedition to a Russian mountain named Kholat Syakhl, camping along the way there. One turned back due to illness, and the other nine were later found dead.
When the bodies were finally recovered, some had unexplained wounds, and the tongue of one woman was missing. Read about the investigation and the various theories about what happened to the campers, at Environmental Graffiti. Link
Caught in a snowstorm, the trekkers veered off course and decided to set up camp on the slopes of Kholat Syakhl – at 5pm on February 2, judging from their photos and diary entries. They went to sleep. Then something horrific occurred, the nature of which we can but guess at. Some have suggested that it was an avalanche, but others aren’t satisfied with this explanation. Only one thing is known for sure. Whatever it was, it was serious enough to make the skiers leap up in the middle of the night and escape from their tent by cutting it open from the inside. Some didn’t even bother to put on clothes or boots as they ventured outside into the bitter cold.
When the bodies were finally recovered, some had unexplained wounds, and the tongue of one woman was missing. Read about the investigation and the various theories about what happened to the campers, at Environmental Graffiti. Link
The avalanche explanation covers everything that happened to the group with the exception of the radiation which could have come from natural sources. The injuries, placement of the bodies etc all point at an avalanche.
Shame there is a mundane explanation for it but there it is.
http://www.cracked.com/article_16671_6-famous-unsolved-mysteries-with-really-obvious-solutions.html
The weird thing about an avalanche is that bodies and other objects are often found on top of the snow rather than buried. It's counter intuitive I know, but that's how it happens.