SKI-ING You can never be certain of the weather you're going to get. But every resort has its own climatic quirks. By William Burroughs
In terms of snow fall, choosing a resort (particularly at the very start of the season) often seems more than a bit of a lottery. Of course, all skiers know how important the weather is but how do we shorten the odds on getting the snow conditions we really want?

The safest approach is very limiting: go to a big, high resort in high season (February/March). Good conditions will be pretty well guaranteed but you will be paying high prices and probably competing with large crowds to get to the snow. Yet there are plenty of other options. Leaving aside the good bets such as Val d'Isere, St Anton, Mammoth, Vail or Whistler, the choice locations include lower alpine resorts, the Pyrenees, Eastern Europe, Scandinavia, New England, and even Scotland.

Starting in the Alps, the snowline descends going east, so the snow statistics for Megeve at 1100 metres are comparable to those for Kitzbuhel at 800 metres. At these levels snow cover can be expected on average between mid-December and late March, with a maximum depth of around half a metre in mid-February. A thousand metres higher, the season will be a couple of months longer and the average maximum depth is over a metre in March.

There are, however, considerable fluctuations on top of these broad patterns. The French Alps are less reliable south of Grenoble, as are the Italian Alps and the Dolomites. There are also interesting local variations. The Haute-Savoie, central Switzerland around Andermatt, the Glarner Alps, the Arlberg, and the Kitzbuheler Alps have notably more snow, while the Otztal, Engadin and the Saas Fee/ Zermatt area are particularly dry.

In the Pyrenees you need to go some 500 metres higher to get snow comparable to the French Alps. In eastern Europe, Romania and Bulgaria are on a par with the lower Austrian resorts, while the High Tatra in the Czech Republic are that bit colder, which makes for slightly more reliable snow. Even lower temperatures in both Norway and Sweden guarantee better snow, but the short days and biting cold can make resorts here in mid-winter spartan, to say the least.

Crossing the Atlantic, the snow conditions of the north eastern United States are bedevilled by the switchback weather. So although the bigger resorts have gone to great lengths to be able to make huge amounts of snow, they cannot get away from the fact that sometimes it is far too warm and at other times it is stunningly cold. Quebec has more reliable snow, but at the price of even more arctic weather. You need to go all the way to the Rockies or the West Coast ranges for an equable mixture of sun and good snow.

Then there is Scotland. Here the combination of relatively high temperatures, frequent strong winds and lack of sunshine mean good conditions are rare. But the plus point is that the season stretches well into April. The best skiing is usually found late in the season as the days lengthen and the Atlantic gales tend to abate.

So far all these observations relate to climatological averages. But, as we all know, in the real world things are hardly ever normal. Snow conditions can show huge variations from year to year and rapid fluctuations within any season, and it is these we have to consider when planning our holidays.

Until reasonable snow cover has built up, it is bound to be risky going to low resorts. Snow depths are less variable later in the season, so as the base builds up in any particular area, the risks decline. Although a sudden thaw can make a mess of the snow, only on the lowest slopes will it be stripped away. So most of the skiing, and even the runs back to the village should remain in working order for weeks rather than days ahead.

William Burroughs holds a doctorate in Atmospheric Physics and is the author of Mountain Weather (Crowood Press, pounds 10.99)