Avalanche Handlers in Chamonix

Avalanche on Annapurna 2 set me thinking about climate change. Ozone. Melting glaciers. Villagers in the valley. Unfortunate climbers. In Chamonix, hearing avalanche control explosions rocking the valley most mornings, I wondered just exactly who did the bombing and how.

At Chamonix’s Office de Haute Montagne, Christophe Boloyan told me. 15 years a Chamonix mountain guide & ski patroller, he’s modest, knowledgeable and loves his job. A rock climber from the south of France, at 19 he came to Chamonix and saw ski patrollers out on the mountain. He soon took the French national explosives qualification and started work.  Christophe laughingly says ‘only smart people should handle explosives, if you get caught drink-driving you lose your certificate!’ I see the point. Both driving and throwing avalanche bombs can kill people.

Chamonix feels like the spiritual home of Alpine extreme sports. Jagged almost savage shards of rock overlook the town. The 4,810m peak of Mont-Blanc is the highest in western Europe, just out of sight but omnipresent. Cham has an illustrious history: One of the Europe’s earliest extreme sports resorts, in 1924 it held the first winter Olympics. In 1955 it opened  then the highest cable car in the world, to the 3842m Aguille du Midi.  It’s the same with tackling avalanches. 30 years ago Chamonix was the first Alpine resort to follow the USA and use helicopters for avalanche control. There’s still a yearly ski patrol exchange with US ski resorts.

Christophe is one of a team of around 70 ski patrollers, with 40-50 working daily shifts in Chamonix’s four ski resorts. Some get to work at around 7am to set off the Gazex and Catex avalanche systems. These are permanently installed on avalanche-prone terrain above ski runs. Gazex pipes explode a mix of propane and oxygen, and the Catex systems are mini cable-lifts, transporting explosives to the right spots for detonation. Along with helicopters, these remotely operated methods are the safest options, always used before patrollers head out on skis.

At 8am, the rest of the team arrive, load up their backpacks with explosives and set off in twos. They follow Chamonix’s detailed avalanche control plan or PIDA, developed from a century of local experience. Patrollers are busy when it has snowed a lot, but also when it’s windy, increasing avalanche risk. They ski every avalanche-prone area threatening marked ski runs. Checking the snowpack, releasing slab avalanches with ‘ski-cuts’ and using their collective experience, patrollers judge whether to ‘shoot’ a site with explosives or not. Teams combine more experienced, usually older patrollers with the less experienced, and they discuss each site together. If one thinks ‘yes, shoot’ and the other thinks no, the fail-safe option is to bomb the site.

French rules require that a ‘last chance’ rescue team is always stationed above the active avalanche team, so two patrollers stay at the highest accessible point in case needed for an avalanche rescue. Having bombed a site, the active team then ski-cut across the slope to make sure it’s safe.

Christophe points out that the explosions aren’t necessarily a guarantee of safety. There’s still a lot to learn about snow and he’s seen slopes avalanche fatally on skiers, only hours after being bombed and ski-cut.  At least in his 15 years no ski patrollers have been lost to avalanches despite most getting caught in one at least once a year. Of course they always minimise risk, staying high up on unstable slopes, making sure there’s not too much snow above them – wear inflatable avalanche bags and carry beacons, probes and shovels.

Helicopters play a major role, especially where there are ski slopes higher than the highest lift. That means it’s hard for patrollers on skis to get to them. Like at Le Brevent, over 80 years old & Chamonix’s original resort. Unlike lower slopes which quickly get packed down by lots of skiers, the Brev’s hard-to-reach upper slopes don’t get packed so well and can prove unstable and tricky to control, threatening the ski runs below.

The helicopter solves the access problem and can be seen buzzing industriously over the Brevent most days. To protect the piste-grooming ‘snow cats’ which work at night, choppers and Gasex/Catex systems are sometimes also used before dusk, after the pistes are closed.

Avalanche control by helicopter used to mean flying with 50 fused sticks of dynamite aboard – which sounds hairy, but according to Christophe isn’t really. Dynamite is pretty stable and needs the high intensity heat of an internal ‘cap’ going off to fire it. Patrollers would light two metre black powder fuses on the 2.5kg sticks, chucking them into avalanche risk areas from the aircraft. That length of fuse gives you a couple of minutes grace before the explosion. On the ground, a 1.5m fuse is the norm. If a bigger charge is needed, two sticks are strapped together.

However the arrival of a French invention called the Daisybell three years ago changed things. Hanging 15m below the chopper, the Daisybell carries cylinders of hydrogen & oxygen. Buttons on a control panel in the chopper fill its conical chamber with a mix of H2 and O2. An infrared sensor tells the pilot when the Daisybell is 1-3 metres from the snowpack and the patroller hits a button and ignites the mix.

Christophe has seen the device improve each year and says the 2013 model is virtually perfect, with enough explosive power to trigger avalanches really effectively. The H2/O2 mix explodes to form just water, a much more environmentally friendly way of working than using explosives. And like the Gazex & Catex systems, it keeps patrollers out of the way of avalanches. So the Daisy Bell is good for everyone in the valley – apart from people who want a lie-in.