Size isn't everything, but it does help to have lots of space in which to ski. Stephen Wood runs his calculator over the big resorts in Europe and the US

They calculate things differently in the United States. Not just in the accounts of big corporations and at election time in Florida; in ski resorts, too. If, say, you want to compare the altitude of Val Thorens in France – the highest resort in the Alps – with that of Breckenridge in Colorado, you have to get out a calculator. Because, while altitude is recorded in metres throughout the Alps, the USA uses imperial measures. Oddly, Canada does the same, although it is otherwise a metric country.

They calculate things differently in the United States. Not just in the accounts of big corporations and at election time in Florida; in ski resorts, too. If, say, you want to compare the altitude of Val Thorens in France – the highest resort in the Alps – with that of Breckenridge in Colorado, you have to get out a calculator. Because, while altitude is recorded in metres throughout the Alps, the USA uses imperial measures. Oddly, Canada does the same, although it is otherwise a metric country.

Working out that Breckenridge is 2,056ft (or 627m) higher than Val Thorens is relatively simple. Comparing the amount of skiing offered by resorts on either side of the Atlantic is more problematic, because in this case it is not only the unit of measurement that differs but also the method. Characteristically, Alpine resorts boast how many kilometres of piste skiing they offer; in North America, the figure published in a resort's promotional material is usually the size of the ski area, in "skiable acres".

But if you ask them, Alpine resorts will tell you the size of their ski area. And their figures make an interesting comparison with those for North America. Vail, in Colorado, reckons to have the biggest ski area in the US; but its 5,289 acres fall far short of the 24,700 at La Plagne in France. And when the lift connecting La Plagne and nearby Les Arcs opens next season, the combined ski area created will be more than six times as big as Vail's.

The biggest area in the whole of North America is Whistler/Blackcomb's, in British Columbia; it has 7,071 acres of skiing. But Les Trois Vallées in France, widely accepted as the world's biggest ski area because of its 600km of pistes, offers 29,391 skiable acres (a total which, interestingly enough, is almost 4,500 less than that of the combined La Plagne/Les Arcs area).

These statistics might come as a surprise and something of a disappointment to those British skiers who spend the extra time and money going to the western US and Canada instead of the French Alps. For one of the enduring attractions of North American destinations – which took a steadily increasing share of the UK ski market through the 1990s – has been the wide-open spaces and the lack of crowding. East Coast resorts are different, and set on a smaller scale; but out west the skiing is easy (figuratively, at least), the mountains big, the apartments huge.

The fact is that skiing in North America is more languid than in the Alps, more like a holiday activity. Consistently good service and accommodation, fast lifts and rigorous lift-queue control, uncommon friendliness and a common language all combine to make the resorts more restful than Alpine ski villages. The food can be very good – I haven't found any mountain restaurant better than the Alpenglow Stube at Keystone in Colorado, despite years of trying – and it's cosmopolitan, too: you can get sushi on the mountain at Whistler/Blackcomb. (There was a sushi restaurant last season at Gstaad in Switzerland, but it closed for lack of interest.)

And even if the total area available on the mountains may be limited, most skiers still have more than enough space. Skiing one Sunday in Sun Valley, in Idaho, I was struck by the sparsely populated slopes, and commented on them to a fellow skier on a chair-lift. (Another big plus for North America; sociability on chair-lifts.) This was, he said, because the Super Bowl gridiron football game was taking place that afternoon. But the resort told me, the following day, that there had been 3,300 skiers on the mountain. Although that was above the daily average of 3,000, it still left almost two-thirds of an acre on the mountain for every skier.

To generalise about North American skiing is a risky business; but at least it is safe to say that the variety of the resorts is one of its assets. East Coast resorts are smaller, less challenging and have a lot of man-made snow (but sometimes not much natural stuff). They are also prone to violent changes in temperature – only once in my life, at Killington in Vermont, have I judged the weather to be too cold for skiing, and that was the day after a thaw. Some of the eastern resorts, notably Stowe in Vermont, have villages that live up to the image of New England charm; many are merely ski areas with accommodation along a main highway. Only Tremblant, near Montreal, has something of the atmosphere and convenience of an Alpine resort, thanks to its remarkable ersatz village created by Eldon Beck, the world's leading ski-resort planner.

Further west the resorts and the mountains are bigger, the snow more reliable, the temperature more consistent. Flight times from Gatwick and Heathrow increase, as do the costs – although there are regular charters to Calgary airport in Canada, giving access to a range of Rocky Mountain resorts including Lake Louise and Banff, Jasper, and awesome Fernie. British tour operators got burned when, in the late 1990s, they launched charters to Denver, south of the border in Colorado; now there are only scheduled flights, with British Airways' service from Heathrow offering the only non-stop hop.

By far the most popular ski destination in the US, Colorado has several major resorts a few hours' drive from Denver airport; and most British skiers choose to hire a car, in order to ski more than one of them. The most prominent are the four under common ownership: Vail, Breckenridge, Beaver Creek and Keystone (the last a personal favourite because the ski area traverses two valleys on a switchback journey from civilisation to wilderness). Aspen has the greater cachet, thanks to its celebrities and restaurants (see below), and superb skiing on four different mountains; and Steamboat has the virtue of still feeling like a frontier town – it's at least close to the frontier with Wyoming – with, beneath its beautiful ski area, a main street wide enough for a cattle drive.

And beyond? Utah, with legendary snow and still relatively small resorts; Jackson Hole, with the infamous Corbet's Couloir and the famous Amangani resort; peerless Sun Valley; and, north of the border, Whistler/Blackcomb, the most popular resort for Britons in North America, whose computer-designed ski area is probably the best in the world. Having said all that, size doesn't seem quite so important.