To get off-piste, hop aboard a mean mountain machine

Skiers and boarders who bang on about being powder addicts can be a bit of a bore – or so I thought until I caught the bug. Suddenly, I too wanted every descent to be a brochure shot. But this left me with a problem. The best guarantee of a day tracing squiggles in virgin snow has always been heli-skiing and for that you can easily fork out £500 a time.

But now a cheaper alternative is rapidly gaining popularity: cat skiing, where a caterpillar-tracked vehicle takes you to back-country runs. And while helicopter pilots won't fly if the cloud cover is low, a cat can follow logging trails up the mountain regardless of conditions. So I find myself in the resort of Marmot Basin, in Alberta, Canada, heading out with a group for a day with Cariboo Snowcat Skiing, each of us having paid C$400 (£195) for the experience.

This experience is a world away from the swish chalet villages and fine dining of many heli-ski operations. Our driver, Bern, takes us in a pick-up through a timber yard to the cat. First, we must do avalanche training. Continental guides will often just rig you up with a transceiver, but North Americans insist on teaching you how to find a victim. Kerry, one of our two guides, buries a transceiver in deep snow and makes sure we can find it. Only then can we climb up the mountain in the cat.

"Holey moley," says Norm, one of our fellow skiers. "What's up?" someone asks. "He's drooling," another answers. Norm, his nose pressed against the window, is surveying the seemingly endless expanse of fresh snow. Skiers and boarders bang on about powder because skiing fresh, deep snow is a bit like skiing your duvet. It promises soft landings and, best of all, gives you the sensation of floating as you turn. If you have gone off-piste only on normal skis you might beg to differ. But for C$26 (£13) we have hired "fat" skis which transform the experience. These super-wide versions give us extra flotation, letting us experience the weightlessness that the first men on the moon must have felt.

Of course, the journeys up in the cat are much slower than by helicopter, but you can bring lunch and a flask and share tales of derring-do over coffee. I am with a group of Canadians who work for the forestry commission and come here every year. They are pretty advanced skiers and boarders, although Cariboo also caters for intermediate skiers. It's challenging skiing, but we enjoy it all the more for that; our second run is in a forest to make things a bit harder; the third is an avalanche-prone bowl; the fourth a dense forest; and the fifth run has sheer drops as we criss-cross the logging trail. Each has a vertical drop of at least 300m, some are more than 1,000m, with the descents getting progressively steeper. Our sixth and final descent is the most dramatic, with our lead guide Matt taking us to a 45-degree slope.

"There are a few cliffs here, which are about five to 15 feet high," Matt warns us, "but you should be able to avoid them if you take it easy. If you hit one just go straight over it. Don't try to turn." The guiding has been excellent, with Matt and Kerry testing for avalanches on the way, giving us clear directions and making sure we don't stray into danger, or even just end up down the wrong valley.

My heart in my throat, I set off. For this sort of skiing you really have to ski straight down the slope with just a few minor wiggles thrown in, relying on the powder to slow your descent. If you try to turn your skis too much you risk falling over.

I manage to avoid the biggest cliffs until, when I try to avoid a smaller cliff, one of my skis decides to go awol and lands me in the deep stuff. Then I realise that powder, again like my duvet in the morning, is very difficult to get out of.

As we wait for our ride back, we have a chance to reflect on the final advantage of cat skiing. Kerry is busy pumping diesel from the back of the pick-up into the cat – by hand. It takes a fraction of what a helicopter would use. Less painful on the wallet – and the environment.

Compact Facts: How to get there

Colin Nicholson was a guest of the Canadian Tourism Commission (0870 380 0070; ski.Canada.travel /uk ). He flew with Air Canada (0871 220 1111; aircanada.com ), which offers return flights from £785, and used a CanRail train pass, price C$550 (£268) for 12 days' travel through ViaRail Canada (0854 644 3553; viarail.ca). He stayed at Jasper Park Lodge (0845 071 0153; fairmont.com /jasper ), which offers doubles from C$229 (£112) per night. Cariboo Cat Skiing (001 866 766 9228; cariboocat skiing.com ) offers cat skiing from C$370 (£180) per day.

Further information: Visit catskiing.ca.