“TRIED ANY front-side fakeys, yet?” I ask Toby and Sebastian as they skid to a stop at the bottom of the Crap Masegn chairlift, spraying me with snow. “Pulled off any helis, or jibbed a few rails?” Wherever I travel, I try to pick up and use a bit of the local language. However, from the pitying looks my 15 and 13-year-old sons give me, I suspect that my command of 21st-century terrain park vernacular is on a par with my Cook Islands Maori.

We have come to the Swiss resort of Flims for the boys to join the Ultimate Zone ski camp, run by the upmarket tour operator Powder Byrne. The idea is that once teenagers have grown out of ski school and can handle black runs confidently, they need their energies channelled into something new and wacky: “Calling all adrenalin junkies, fakeys, 180s, helis and grabs, we will show you them all and get you into the half pipe and on to the skiercross course!” screamed the flier.

Just the sort of stuff my two were ripe for.

Day one, and the pony-tailed, pipe ‘n’ park cred-oozing instructor Adrian (“call me Adie”) Kobelt greets his six teenage charges with high-fives. Off they all ski, wearing the safety helmets which he insists are mandatory, and cannily suggests are cool by wearing one himself.

They have also all swapped their carving skis for double-tipped ones that allow you to land and ski backwards — a signal that Adie intends serious business in the resort’s huge Crap Park. (The resort squeezes every drop of publicity out of the fact that in the local Romansh language the word for mountain peak is “crap”, hence the Craplift, Crap mountain restaurant and so on.)

Snow parks, fun parks, terrain parks, call them what you will, these mountainsides bulldozed into half-pipes, jumps and motley obstacles have for several years been staples of every serious ski resort. What seems to have changed recently, however, is that young “freeriding” skiers are as much at home here as snowboarders.

Later that first morning, I glimpse the Ultimate Zone gang from a chairlift, wiping out in their heroic first attempts at “doing airtime” and fakeys (landing backwards). After lunch, they head for the notoriously steep and gnarly “freeride routes” — ungroomed tracts of mountainside within the ski area — of a kind common in North America but rare in the Alps.

The Ultimate Zone, it rapidly becomes clear, really is for teenagers thirsting for a challenge. Anybody not up for it can downsize to Powder Byrne’s more laid-back Snowzone club.

This is exactly what half the group do on the second day, leaving just Toby and Seb plus Alex Crouch, a 14-year-old girl brimming with brio. If the three of them are a touch disappointed to lose the camaraderie of the rest of the group, getting Adie and his expert instruction all to themselves is ample compensation.

One day they swap their skis for snow blades, the better to practise stunts involving spinning in the air, before heading for the trails that wind through pine forests on the lower slopes. I overhear Toby chatting up Alex with lines like: “You nearly did a 270 there! Why not try a 360? Some dude did a 540.” Who would have thought that the youth of today would take to their 90 times table with such alacrity?

But for all the antics in the terrain park, the best day — no contest — comes after an overnight snowfall. On a morning when the peaks of Vorab and La Siala rise like islands from a sea of cloud below, Adie leads the trio off piste and into the virgin snow. From a distance I watch them forming pairs and cascading down the mountain, weaving in and out of each other’s fresh tracks to trace linked figures of eight in the powder. To me these “powder eights” seem like feats of synchronisation, symmetry and style to beat anything achieved in the terrain park. As Sebastian says later: “Oh, it’s easier than it looks, but it is the biggest buzz ever to, like, float — no, fly! — through snow.”

On Thursday there is a break from the Ultimate Zone for families to ski together. The five of us (including my wife Hennie and daughter Iona, 17, a gentler skier whose idea of a holiday runs contrary to the disciplines of ski camp) spend a marvellous day taking the lift up to the sunny, 3,018m (9,900ft) heights above the Vorab glacier, to ski the 14km (nine miles) black run that plunges down some precipitous drops and snakes through a steep-walled gully. For people like me, who like to plan a route and put some serious mileage under their skis, this is the best piste skiing that the resort has to offer.

Strangely, Flims is almost unknown outside Switzerland and Germany, hosting just a few hundred British skiers per season — most of them Powder Byrne guests. And yet it is one of the largest, and most snow-sure ski areas of Switzerland, barely 90 minutes by road from Zurich airport. The 220km of prepared piste are shared with the linked Graubünden Canton villages of Laax and Falera, last refuges of Romansh.

When the teenage gang meet for some après-airtime, first stop is to check out the funky Crap Bar in Laax village, a short bus ride away from the more sedate Flims, where we are holed up in wood-panelled rooms in the cosy, family-run three-star Waldeck Hotel.

In truth, however, Toby and Sebastian seem much happier joining in the activities organised by Oli Bentley, Powder Byrne’s hip young staff member, for their teenage guests. One evening they all pile into a minibus and head for the Flims High Ropes Centre to test their skills as trapeze artists. On others, they settle for what teenagers really enjoy most after a day on the slopes — eating pizza and hanging out together, doing nothing in particular.

By the end, the Ultimate Zoners have, as promised, learnt to perform a bewitching array of snowy, airborne tricks. As the week progresses, Toby, Sebastian and Alex persuade Adie to spend less time in the terrain park, and more off piste, on the freeride routes, and clocking race times on a giant slalom course.

Their collective verdict on the Ultimate Zone: “Awesome . . . it totally rocks”; on Adie: “a ledge” (as in “legend”). And on the resort generally, they merely quote from the official marketing slogan that proclaims: “Flims is Crap”.

Even I understand that this is a verbal thumbs-up.

Need to know

Martin Symington and family travelled with Powder Byrne (020-8246 5300, www.powderbyrne.com). Ultimate Zone camps will run in Zurs (February 10-17), Flims (February 10-24 and March 31-April 7), and Zermatt (February 11-18). Costs: £330 per person (£335 in Zermatt), for five full days’ instruction. Participants must be over 13 years of age, and confident black-run skiers. The company runs a range of other clubs and courses for children and teens of other abilities and interests, including a “Boardzone” for snowboarders.

A week’s half-board at the Hotel Waldeck starts at £856, rising to £1,148 leaving on March 31 and £1,494 on February 10. Lift passes: Six-day passes for the Flims-Laax-Falera area cost £146 per adult and £98 for 13-17s.

Further Information: www.flims.com and www.laax.com.

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