I imagined the tragedy as divided into two phases:
a first phase due to man, a second phase due to nature.
In the first phase: Two people in the group are outside the tent (guard duty or just for their need), so they decide to make a joke to the rest of the group. The joke can consist of throwing some snow on the tent and shouting at the avalanche, or simply alerting the group of an imminent danger. This can cause some of them to suddenly panic enough to break the tent to flee and head downstream. At this point the two who made the joke understand that the thing got out of hand and that with the cuts to the tent they caused very serious damage so they continued in their skit, also reaching the group and joining 50 meters from the tent (I was reading some tracks that would demonstrate this). Once united with the group they did not find the courage to tell them the truth for fear of being attacked. So they didn't tell the group it was a joke. They thought that after some time everything would calm down and they would all go back together to the tent to repair it and take the remaining things but this did not happen because at this point phase 2 takes over, or the nature that prevents them from comfortable return to the tent causing the death of some from hypothermia and others from bruises following a fall in a high ditch.