Avalanche injured two skiers in the French Alps.

Two skiers have been injured in an avalanche at the Valfréjus ski resort in the Savoie Department of France on Saturday 23 November 2019. The incident happened on the Col ski piste above the Arrondaz Plateau at an altitude of about 2300 m above sealevel. The injured skiers are reported to have been part of a party of three pensioners from Lyon, plus a guide in their 30s. They were dug out by friends and airlifted to a hospital in Saint-Jean-de-Maurienne. The incident is reported to have been caused by a layer of loose fresh snow forming above a more compacted layer of older snow, with little adhesion between the two layers, so that the upper layer gave way when disturbed.

The approximate location of the 23 November 2019 Col d'Arrondaz 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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Twelve-year-old skier survives despite being burried by avalanche for 40 minutes.

A twelve-year-old boy from London has survived despite being buried under snow for 40 minutes following an avalanche at the ski resort of La Plagne in the Savoie Department in the Auvergne-Rhône-Alpes Region on Wednesday 26 December 2018. The boy was part of a group of off-piste skiers (people skiing away from a marked trail) but had become slightly separated from the group when he was hit by the avalanche, which swept him about 100 m from where he was last seen, making it impossible for the rest of the party to locate him. Despite this, and the fact that he was not wearing an avalanche detector, he was located after about 40 minutes by a Belgian Malinois rescue Dog. The boy was airlifted to a local hospital by a rescue helicopter suffering from a broken leg, with local authorities describing his survival as 'miraculous', since very few people survive for more than about 15 minutes after being buried by an avalanche.

A Belgian Malinois rescue Dog searching for an avalanche victim. Gendarmerie Nationale/Facebook.

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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Father and daughter killed by avalanche in French Alps.

Two skiers have died in an avalanche while skiing on the Pisaillas Glacier near Val d'Isère in the Savoie department in the Savoie Department of southeastern France on Sunday 19 February 2018. The as yet un-named pair have been identified as a father and daughter from the Paris area aged 43 and 11. It is not clear why they were on the glacier at the time of the avalanche, as it had apparently been closed to skiers following recent heavy snowfall. 

Pisailles Glacier, near Val d'Isère, is popular with skiers and provides year-round skiing due to its high altitude, but is considered dangerous after heavy winter snowfalls, due to the high risk of avalanches. Benoit Launay/Le Dauphine.

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.

The Alps have seen a number of avalanche related incidents this winter, largely due to high levels of snowfall. This is, in turn caused by warmer conditions over the Atlantic, which leads to higher rates of evaporation over the ocean, and therefore higher rates of precipitation over Europe, which falls as snow in cooler regions such as the Alps.

In a separate incident two hikers were injured in an avalanche near Col de Fenestral in the Valais Canton, also on Sunday 18 February, and are being treated in a local hospital with non-life-threatening injuries.

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