By James Cove
BBC News in the French Alps
Fifty three people have died in avalanches in the French Alps so far this year, making it the worst year since records began 35 years ago.
Mountain safety courses help skiers to recognise dangerous snow
Last week a 35-year-old British woman died snowboarding off piste in Les Arcs.
She was carried 150 metres down the mountain when the slope she was on with her brother slid - she was only a few metres from the marked run and was found buried beneath the snow 45 minutes later by a rescue dog.
Her death marked a grim statistic as the death toll is now double last year's and is set to rise as the snow melts in the spring.
During one three-day period, from 20 to 22 February, 12 people were killed by avalanches and many more had narrow escapes.
France is the most popular destination for British skiers and, so far, half a dozen of the victims have been British.
"The conditions this year in France have been very unusual," Nigel Shepherd, a British mountain guide and the Alpine safety adviser to the Ski Club of Great Britain, told BBC News. "The snow is sitting on a very unstable base so it is highly prone to avalanche."
The first major snowfall of the season occurred in mid-December but then, unusually, it remained very cold so the snow turned into granular, sugary crystals which are very unstable - so later heavy snowfalls in February and March have been sitting on highly unstable foundations.
Earlier this year, when I was on a mountain safety course, I dug a pit into the snow to see the base and I could literally scoop it out with my hands. This type of snow is called depth hoare and can be highly dangerous.
Nigel Shepherd says conditions have been unusual
The conditions this year have been less treacherous in Switzerland but still 22 people have died in the snow there. Sixteen have perished in Italy, 10 in Austria and six in Germany. In one of the worst incidents in recent times, four people were killed in an avalanche in the Andorran resort of Pal earlier this month.
In Tignes and Val D'Isere the authorities estimate that half the skiiers go outside the marked runs.
New developments in equipment mean people with less experience can get to remoter areas but some do not carry or know how to use the safety equipment. They should wear an avalanche transceiver that emits a signal, and carry a shovel and probe to find and dig someone out.
Rules need tightening?
"People who get buried in avalanches have about 15 minutes before suffocating. This is usually not enough time for the rescue services to get there so people need to rely on their skiing companions," advises David George from ski website PisteHors.
"That means people must have the right equipment and be practised in using it".
The alarming rise in the death toll is raising serious questions about whether rules need to be tightened on where people ski and how they behave. Some French resorts tried to ban off piste skiing a few years ago but were unable to enforce it.
People sometimes duck under safety ropes in search of fresh snow but are rarely reprimanded. A handful of skiers in France who have triggered avalanches have been prosecuted for acting irresponsibly and endangering lives.
The heavy snowfalls have also caused severe transport problems. Earlier this month Val Thorens, Les Arcs, Tignes and Val D'Isere were cut off as avalanches fell across the roads.
Thousands of people were stranded and spent the night in sports halls and schools down the valley in Bourg St Maurice. The French army was called in to help and extra trains provided sleeping accommodation in the sidings.
Off piste looks tempting but can be dangerous
In the worst incident a rockfall hit a car, killing two children, aged 10 and 14. Several coaches skidded off the road but no-one was hurt. In Switzerland Zurich airport was closed for several hours and the normally efficient Swiss railway system was disrupted by avalanches.
More snow is forecast to fall across the Alps in the run-up to the Easter, making it one of the snowiest winters in recent years there.