Here is our choice of ten classic extreme off-piste descents in Europe and North America, and a word of warning: at the risk of stating the obvious, do not ski off-piste without safety equipment and ideally we recommend you hire a qualified mountain guide.
Ride the cable car from St Anton to Galzig, then switch to a second main cable car that flies high above the ski area to Valluga II. From here a five-man gondola carries you the last few hundred metres to expert-only terrain and the notorious Valluga Nord off-the-back descent to Zurs. To ride the gondola with skis or a board to the observation platform at the 9,220 foot summit, you must be accompanied by a recognized mountain guide. Once at the summit, you have a few gut-churning minutes to compose yourself before tackling the 40-55 degree north-facing convex pitch. The initial descent to Pazieltal is the gnarly bit: depending on conditions, the skiing itself is not so tough, except for the fact that there is a series of cliffs below, hidden from view: falling here is not an option.
South-west Montana is a long way from most places, but if you're looking for expert terrain far from the madding crowd, Blue Sky's 11,166-foot Lone Mountain will not disappoint. The 15-man Lone Peak aerial tram carries you to the summit where you have two choices: sneak back down in the tram, or embark on a double-black-diamond just about every other way. Ski the chutes and gullies as a warm-up, then if you're up to it - and provided you have the appropriate rescue equipment (shovel, probes, transceiver and a partner) - switch to the front face to tackle the 42-degree, 1,450-foot Big Couloir - narrow, rocky, no way of bailing out once committed and no margin for error.
Without doubt North America's best-known double-black-diamond run, Corbet's Couloir starts with a gut-wrenching 10-20 foot vertical drop off (that means you jump!) into or onto a 50% degree pitch. It's your landing on entry and holding on through a well-executed first turn that determine whether you get the chance to make a second turn or fall like tumbleweed all the way to the bottom. There are steeper and more difficult descents nearby in the expert chutes from Thunder Quad, but, as trophy runs go, Corbet's Couloir is an extreme classic and a 'bragging rights' collectors' item.
It's quite a hike to get here, but experts may consider the journey to Mammoth worthwhile, especially after riding the Panoramic Gondola to the 11,053 foot summit. From here head right to the Upper Bowl and a series of dramatic steep chutes, most famous of which is Hangman's Hollow. Best tackled when there's enough fresh snow to cushion your landing, there's no way in except to jump and make a perfect first turn in the elevator-shaft-like chute lined with rocks, before opening out into the bowl below.
Although usually associated with glitz and glamour, the four mountains of Aspen Snowmass boast the biggest vertical drop in the U.S. There are great opportunities for expert skiers and riders at Snowmass, Aspen Mountain and at Aspen Highlands, but the choice of local experts is the 12,392-foot Highland Bowl with more than a dozen chutes of 40 - 45 degrees dropping over 1,000 feet. Highland Bowl offers the steepest inbounds off-piste experience of any U.S. ski resort; and new terrain is opened each year. The bowl is reached by an occasional free snowcat ride from the top of the Loge Peak chair to the first access gate, or a 20-60 minute hike. There are plenty of places where you can drop in to the left of the ridge, but beware: the steep and narrow chutes of Marron Bowl to the right of the ridge are uncontrolled and avalanches in this area have claimed many lives over the years.
One of Europe's top ski resorts, Val d'Isère (Espace Killy) also presents some of the best off-piste in the Alps and some superb guides. The 3,000-foot vertical La Banane, for example, is easily reached from the main Piste de la Face from the top of Bellevarde. A guide will know whether it's safe to ski, and will even render it safe if he knows what he is doing, by cutting or triggering a small avalanche. One man who certainly knows what he is doing - and is used to 'preparing' La Banane in this rather extreme manner - is Pat Zimmer, the founder of Top Ski, which has a long tradition of taking clients to the best off-piste runs in the region.
American-style extreme skiing was discovered here in 1984, when Warren Miller captured Scott Schmidt on film jumping 100 feet from the Pallisades at the top of Squaw Peak. If you want to access the Pallisades and take to the air yourself, you should ride Headwall or Siberia lifts to the top of Squaw Peak then hike up to the summit to the series of north-east facing narrow chutes that line the cliff. For voyeurs the busy Siberia Bowl is a perfect vantage point from which to observe the making or breaking of extreme skiers throwing themselves off Pallisades cliffs.
High above Argentière, the skiing on Les Grand Montets is steep and ungroomed, especially Point de Vue or Pylônes, the two main options for skiing or boarding the face. The panoramic view of the Mont Blanc massif alone is well worth the 120-stair climb to the observation deck. For the safest lines and to find the best conditions - or simply to stay alive - you are advised to hire a mountain guide if skiing or boarding 'off-the-back'. West (right) of the steps is Pas de Chevre - over 4,500 feet of stunning descent under L'Aiguille Dru to the Mer de Glace. It's best tackled in the afternoon, but leave enough time and don't underestimate the scale of this descent. The steepest part is in the narrows near the beginning, though the crux is negotiating the moraine gully exit onto the Mer de Glace. Usually short of snow and seldom pleasant, it's worth tackling nevertheless for the awesome skiing above.
Blackcomb Mountain's Ruby Bowl reigns supreme for a double-diamond adrenalin buzz. From the top of the Glacier Express lift, shoulder your skis and start booting up along the precipitous Spanky's Ladder to the entrance of Ruby Bowl's 2,000 north-facing vertical feet of continuously steep dry powder. In perfect conditions it's just bliss!
A mountaineering centre rather than a ski resort, La Grave scores low on most counts except for the steep glacier-coated terrain of La Meije, home to hardcore extreme skiers, but also the scene of many tragic accidents. Ungroomed, rugged and neither protected from avalanche nor patrolled, the 'ski area' is reached by a 30-minute cable car, then a couple of drag lifts, before a gnarly scramble over rock and ice brings you to Trifide Couloir, plunging 50 degrees for more than 3,000 feet. Fasten your helmet and don't fall.