Four Indian soldiers and two civilian porters have been killed in an avalanche on the northern part of the Siachen Glacier in Jammu and Kashmir, India, on Monday 18 November 2019. The casualties were part of a patrol that was hit by the avalanche at about 3.00 pm, local time, in an area at an altitude of 5800 m above sealevel. All of those caught in the avalanche were evacuated by helecopter, but only after several hours, which is likely to have been a contributing factor in the loss of life in an area where temperatures can drop to -60°C at night. Seven other soldiers are described as being in a critical condition.
The approximate location of the 18 November 2019 Siachen Glacier avalanche. Google Maps.
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.
Diagrammatic representation of an avalanche, showing how layering of snow contributes to these events. Expedition Earth.
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