Each machine costs around &8364250000 about £145000 and uses 25-30 litres of diesel per hour during which time

Each machine costs around €250,000 (about £145,000), and uses 25-30 litres of diesel per hour, during which time it can thoroughly groom two hectares of slope.The numbers are staggering. In this area, all night, every night, 21 chenillettes are driven by 41 drivers, working separate shifts either between 5.30pm-1am, or 2am-9.30am. In the Courchevel-La Tania area there are 140km of runs, amounting to 528 hectares of piste. Courchevel is just one part of the Trois Vall?, and it incorporates its lower neighbour, La Tania The other two valleys are that of Meribel and Val Thorens. The machines are so designed that even on the steepest slopes it is almost impossible for them to slip or flip. There has been, to date, not a single accident in the Trois Vall? involving a chenillette I was still concerned, however. There is a run in the Courchevel valley called M, which is so steep I couldn’t imagine any vehicle, however brilliantly designed, being able to tackle it safely.”Surely you can’t drive up and down M all that easily,” I said to Jean.”Non,” Jean agreed, adding, with typically Gallic nonchalance, “c’est difficile,” and he explained that there are, dotted around the valleys upon the most precipitous slopes, 220 anchorage points to which the machines can be attached.The Trois Vall? is the largest ski area in Europe, and its slopes are thought to be among the most well-maintained and beautifully groomed in the world.

All the operators of the chenillettes are highly trained technicians, and most of them are experienced skiers and mountaineers: they know exactly how the snow should be.Nothing, it seems, is too sheer or too awkwardly angled for the chenillettes. Once the snow has been relocated, the chenillette is driven over it, tamping it down beneath its aluminium caterpillar tracks, while at the back of the machine giant combs are dragged through the newly ploughed snow, smoothing it out into wide, gently rippled tracks – absolutely perfect for skiing on. The process is called remonter la neige, which translates as pushing the snow back uphill. You don’t think about why until Jean points out that when skiers ski, they bring all the snow downhill with them, or push it to the sides of the piste.In tandem with the scoop, Jean skilfully operated two fin-like attachments at either end of it – a bit like flippers on a pinball machine – that angle the snow precisely, depending upon where it is most needed. Not comfortable.Jean’s window was open, ostensibly to let in fresh air, but the chenillette’s chimney was not far from it, and all that came in was potent diesel fumes. It was also incredibly noisy, like being stuck right in the midst of busy road-works.

The most frequently used is the wide scoop, which works like a giant shovel, gathering loose snow from the piste edge and pushing it back on to the slopes in enormous mounds. We had to shout above the grind and clamour of the engine.At the front of each chenillette is an array of heavy-duty attachments. One for him, obviously, and one, it turned out, for my husband, as he’s bigger than I am; I was the only one of us small enough to perch on the dashboard. In the evenings, from the dining-room of our hotel in Courchevel 1850, my husband and I like to watch the winking lights of the piste-bashers. These vast, wide machines (which look, with their caterpillar runners, like a cross between army tanks and combine harvesters) make their way up the mountain to restore the pistes for the following day’s skiers and snowboarders.
But often we have wondered, when watching the machines’ steady progress up the blackened mountainside: how many of them are actually out there? How much do they cost and how much fuel do they use? And how long does it take, for example, to groom our beloved run, Creux? The meticulous care of the slopes for which the Trois Vall? ski area is rightly renowned consumes a substantial part of the price of your ski pass. It was Jean who would take us up the mountain and explain to us what he did, bringing us down again at nine, when he took a break for supper.The machine into which we climbed is known to the British as a piste-basher; in French it is a chenillette Jean’s chenillette had two squashy seats, with suspension.

Could we, we wondered, perhaps accompany a driver on a route up the mountain at night? We were fascinated by the process and the mechanics of slope-grooming. “Pas de probl?,” said Bianchi.So at five the following afternoon, we met at the office and were introduced to Jean, an experienced driver who is in charge of coordinating much of each night’s work. But what are the costs (both financial and environmental) to the local area, and to the Alps as a whole? What price the pleasure of our annual sporting luxury?After several years of speculating, we decided to find out. So we went to the Soci? des Trois Vall? main office, and managed to speak to the person in charge, Gilles Bianchi, the chef de damage (damage comes from the verb dammer, meaning to tamp down). High above Courchevel, in the Trois Vall? in France, lies my favourite ski run, Creux.