Two of the victims were still alive when rescuers pulled them out of the snow, but died soon afterwards. The avalanche, which was 400 yards long, happened on an off-piste slope at an altitude of 2,100 metres, within sight of hotels and a short distance from a beginner-standard green run.
Most avalanches happen during or soon after a storm. Snowstorms and rainstorms are important contributors to avalanche danger. Heavy snowfall will cause instability in the existing snowpack, both because of the additional weight and because the new snow has insufficient time to bond to underlying snow layers. Rain has a similar effect. Rain causes instability because, like a heavy snowfall, it imposes an additional load on the snowpack; and, once rainwater seeps down through the snow, it acts as a lubricant, reducing the natural friction between snow layers that holds the snowpack together.
Preventative measures are employed in areas where avalanches pose a significant threat to people, such as ski resorts. There are several ways to prevent avalanches and lessen their power and destruction; active preventative measures reduce the likelihood and size of avalanches by disrupting the structure of the snowpack, while passive measures reinforce and stabilize the snowpack in situ. The simplest active measure is repeatedly traveling on a snowpack as snow accumulates; this can be by means of boot-packing, ski-cutting, or machine grooming.
Explosives are used extensively to prevent avalanches, by triggering smaller avalanches that break down instabilities in the snowpack, and removing overburden that can result in larger avalanches. Explosive charges are delivered by a number of methods including hand-tossed charges, helicopter-dropped bombs, Gazex concussion lines, and ballistic projectiles launched by air cannons and artillery.
Passive preventive systems such as snow fences and light walls can be used to direct the placement of snow. Snow builds up around the fence, especially the side that faces the prevailing winds. Downwind of the fence, snow buildup is lessened. When there is a sufficient density of trees, they can greatly reduce the strength of avalanches. They hold snow in place and when there is an avalanche, the impact of the snow against the trees slows it down. Trees can either be planted or they can be conserved, such as in the building of a ski resort, to reduce the strength of avalanches.
To get some idea of the unstoppable and destructive force of an avalanche, here’s an example. A large avalanche in Montroc, France, in 1999, where 300,000 cubic metres of snow slid on a 30° slope, achieving a speed in the region of 100 km/h (62 mph) killed 12 people in their chalets which were buried under 100,000 tons of snow, 5 meters (16 feet) deep. The mayor of Chamonix was convicted of second-degree murder for not evacuating the area, but received a suspended sentence.
Here are some top tips from Henry Schniewind, an avalanche expert, on how to survive dangerous snow situations:
Know the danger: rating definitions for the five international avalanche danger levels: 1 – low, 2 – moderate, 3 – considerable, 4 – high, 5 - extreme. There are a series of flags, clearly visible to all skiers, warning of the category of risk, watch out for them.
Read the official avalanche forecast bulletin for your ski area the evening before you head out .
Travel with people who have a similar approach to having fun and being safe off-piste.
Equipment: Have all of the essentials with you an avalanche transceiver, probe and shovel, needed to get your friends out from under the snow in 15 minutes or less – after 15 minutes buried under snow, the chance of survival decreases rapidly.
Train with the safety equipment. Do a two or three hour practical session on how to use your safety equipment and refresh yourself each year.
The phone numbers of local rescue services: have all of them on your phone.
Routes: Have a good idea of the area and routes you'll be skiing (using maps, guide books and your personal experience) so you don’t end up stuck on a cliff.
Slope angles: Know how to identify slopes of 30 degrees or more, on which the majority of avalanches occur.
Talk to local professionals like the ski patrol (piste patrol) to get insider information on the area.
It has to be said that the actual odds of being swept off your feet, so to speak, are admittedly extremely low, but consider that 83% of all accidents are caused by the people involved in the avalanche. It pays to be aware of where you should perhaps not be venturing and recognise where you can lessen your own risks. Should you be unlucky enough to be caught up in the maelstrom. Here are some survival tips from Peter Hardy:
If you’re wearing an ABS backpack, pull the trigger and release your airbag. Hopefully this will keep you on the surface.
Try to ski or tumble to the side out of the path of the slide as quickly as you can.
If possible get rid of your skis and poles (never wear wrist loops in a potential avalanche zone).
The sensation is of being in a high-speed washing machine. Swim furiously for the surface and try to get your head above the snow. Make the biggest effort as the avalanche slows.
Try to keep nose and mouth free from snow and use your arms to establish space around your face before it finally stops.
Avalanche debris has a similar mass to setting concrete and further movement becomes impossible.
If you are completely buried but wearing a radio transceiver your chance of survival is 34 per cent. After 15 minutes this starts to fall dramatically. If you are not fully buried, survival chances are over 90 per cent.
An avalanche is one of Mother Natures spectaculars and, from a safe distance, an awesome spectacle. In the accumulation of billions of snowflakes a deadly force lies dormant, a force that once summoned is unstoppable.