At least 28 people have died following an avalanche in southeast Tibet on Friday 20 January 2023. The incident happened at about 8.00 am local time, when several tonnes of snow slid onto a section of highway between the village of Pai in Mainling County and the Doxong La Tunnel in Medog County, burying dozens of cars carrying people trying to get to family homes for the Lunar New Year celebrations. Rescue workers now believe they have found all of the vehicles hit by the snow, with fifty three people having been found alive, five of them with serious injuries, while the bodies of 28 people who did not survive the event were also found.
Avalanches are caused by the mechanical failure of snowpacks; essentially when the weight of the snow above a certain point exceeds the carrying capacity of the snow at that point to support its weight. This can happen for two reasons, because more snow falls upslope, causing the weight to rise, or because snow begins to melt downslope, causing the carrying capacity to fall. Avalanches may also be triggered by other events, such as Earthquakes or rockfalls. Contrary to what is often seen in films and on television, avalanches are not usually triggered by loud noises. Because snow forms layers, with each layer typically occurring due to a different snowfall, and having different physical properties, multiple avalanches can occur at the same spot, with the failure of a weaker layer losing to the loss of the snow above it, but other layers below left in place - to potentially fail later.
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