Skiing injuries can and do happen when you least expect them, let alonewhen you are taking risks: there are documented cases of skiers breaking a leg as they climb down the aircraft steps before even setting foot in a ski resort. And some years, ago a producer working on a television commercial - in which the hero clutching a box of chocolates had to out-ski an avalanche - fell over and broke her leg while standing on a mountainside watching.

Not so long ago, I met a ski holiday rep who had damaged his cruciate ligament while skiing without even falling over - he hit a bump awkwardly and tore it. Konrad Bartelski, Britain's most successful world cup skier ever, once damaged his cruciate ligament during a race without even realising until he crossed the finishing line. Ligaments, cartilages and tendons are the things that get hurt these days. Thanks to modern equipment, including more and more sophisticated bindings, broken legs are much rarer than they used to be. But something's got to give, and if it's not your leg, it's likely to be your cruciate.

Although advanced skiers travel at speed and are vulnerable to spinal and head injuries, surprisingly it is the beginners who frequently prove to be most at risk. They tend to ski slowly, and more often than not it is the slow, sickening, twisting fall that causes the damage - not the high-speed fall that catapults the skier out of his bindings - unless of course the fall hurls the unfortunate victim against a rock. Which leads us to head injuries, and protective helmets. Are they really necessary? In Scandinavian resorts they are virtually compulsory for young children, and many people believe that adult skiers should also be required to wear them. Yet statistics show that remarkably few skiing accident cause head injuries. They also show that a frightening number of accidents on the slopes are drink-related.

Drink is freely available - and its consumption encouraged - in a host of mountain restaurants. Marco Grass, a member of the Saas Ski School in Klosters, Switzerland, warns: "Drinking when you are skiing is just as dangerous as when you are driving a car. You think you are in control but in reality your reactions are slow and ill-judged. Statistics relating to injuries in this major ski area of Klosters/Davos show that more and more are drink-related. And we have no reason to think this trend is only happening here."

In North America, reckless skiers can have their lift ticket confiscated and even be put under arrest. In practice - unless they actually injure another skier - they often get away with it. Having monitored American skiing in almost 100 resorts right across the continent, the closest I have come to seeing an errant skier being punished was in Snowshoe, Virginia, when a member of the ski patrol leapt onto a chair to catch the culprit but lost him on the mountain.

Colin Allum, whose Fogg (as in Phileas) Travel Insurance Services specialises in skiing insurance, observes: "Skiing is a high-risk sport. About one person in 50 who goes skiing is liable to receive some form of medical treatment during the course of a normal winter-sports holiday. This can range from a twisted ankle or bruised shoulder to the extreme cases of serious back or head injury, or - fortunately very rarely - to death."

If you happen to be first on the scene after an accident, it is important to cross two skis in the snow about ten metres up the slope from the injured skier. Don't try to move the victim, and if there is a leg injury, don't try to remove the boot, as it can act as a splint. Keep the injured person warm, and do not give him or her any alcohol. Knees are the most prone to injury, but almost no part of the human body is immune from one sort of skiing injury or another.

A fracture or damaged cruciate ligament are among the worst things than can happen to your legs: but it is not always the big injuries that cause the most pain and curtail skiing. Some skiers - myself included -endure endless agonies because of ill-fitting boots. Like many other skiers, I am the unfortunate owner of feet that are fundamentally the wrong shape for most boots (one expert boot-fitter in Aspen described them as 'brick- shaped').

I remember cracking, or at least bruising, a rib or two when I was learning to ski in Verbier, Switzerland, and a friend of mine is always damaging hers. You can't do much with cracked ribs except perhaps strap them up, but she always continues to ski regardless. As with many skiing injuries, it is often less painful to carry on skiing than to walk around or even lie down in bed. The same goes for shoulders.

In California, I fell heavily on my left shoulder twice in two days and the pain affected me for months. Skiing was not a problem (except the worry of falling on it again), but lying in bed could be agony. Usually an anti-inflammatory cream and resting it will do wonders in such cases. Wearing a sling can help.

Shoulders are always a problem. They have such a sophisticated collection of moving parts, any one of which may be damaged in an accident without the others being affected. You may find you can ski yourself silly without so much as a twinge, but looking at your watch almost kills you. Still - at least I haven't torn my dreaded cruciate ligament yet (though no doubt it is only a matter of time).

Says Allum: "The advent of quick-release bindings has dramatically reduced the number of fractures - but dramatically increased the number of ligament injuries. In the days when bindings simply did not release, it was almost inevitable that a leg would be broken. Nowadays, 50 per cent of what may be regarded as 'serious' injuries - those which in due course will require some operative treatment - are knee ligament injuries.

So much for the skis. But what about the skier? "There are those of us who may readily admit to being beginners even after 20 years of skiing. And there are others who will only admit to being advanced after 20 minutes," says Allum.

One good way to try to prevent injury on the slopes is to get fit before you go. Enter the Cybex machine, used by better fitness clinics. It sounds like something out of Dr Who, but what it actually does is check the strength of your hamstrings, quads abductors and adductors, and then targets any of these for strengthening with a customised programme of weight-training and exercises.

Weather and altitude can also play their part in making a skier's life a pain. Some people get serious altitude sickness in America, where skiing in the Rockies can mean altitudes of 11,000 or 12,000 feet or more. At such heights it is not unusual to feel some effects, including headaches, nausea, breathlessness etc. These should wear off after two or three days (a good reason not to go skiing in the USA for just a week, as your holiday may well be half over before you're ready to face it), but if they persist you should see a doctor. Drinking plenty of water - much more than you think you need - helps to alleviate the problem. But serious altitude sickness can only be dealt with by getting the patient to a lower altitude as quickly as possible. Your doctor can prescribe tablets to lessen the impact of altitude.

As for weather: watch out for frostbite. I got my first taste of it in Colorado, skiing Breckenridge's peak 7. The trouble is, you don't know you've been affected unless someone tells you. My nose went white, but I had no idea. As a damage limitation exercise, it is important to cover any frostbitten extremity and keep it warm. Experts argue over whether it is better just to cover it or knead it slightly to restore the blood supply. Those against kneading claim it could damage the cells while they are frozen. The consensus is just keep it warm.

Strong sunlight can be a major problem too. Always wear good protective creams, even when it may seem that the sun is not coming out that day. As the saying goes, you may not be able to see the sun, but the sun can see you. Even a couple of hours' skiing in high altitude without protection, especially during the later months of March, April and May, can cause serious sunburn and even sunstroke because of the strong ultra-violet rays.

Much has been said and written of the dangers of skiing off-piste, and it is true that skiers leaving marked trails without a guide may cause avalanches or be caught up in them, or even fall into a crevasse. However, skiing in a resort on a marked run is arguably just as dangerous. When you compare the numbers of people on piste with those who ski off them, the chances of a collision in a resort must surely be just as high as those of falling foul of nature outside a resort.

Almost ten per cent of skiers who end up in Davos hospital have been involved in collisions. And collisions nearly always cause injuries, and sometimes serious ones. I found this out in a very tragic way when my girlfriend Lucy Dicker was killed in La Grave, following our successful mission to ski every day in 1994. Even skiing off-piste with a guide is no guarantee that no harm will come to you. Or to the guide for that matter. There is a cynical saying that all the avalanche experts are dead. Tragically, there is some truth in it.

According to the rescue service SOS which operates in the Parsenn area of Davos - one of the most extensive ski areas in Europe, which also prides itself on its avalanche research centre -"Avalanches are a natural phenomenon and therefore no absolute safety from them can be guaranteed. We must emphasise that even after the most experienced judgement and safety measures have been taken, an avalanche can still break loose and run over an open and marked piste."

Always obey avalanche warning signs and stay out of high-risk areas unless a qualified high mountain guide is skiing with you. He or she will have specialist knowledge and will certainly not take you off-piste if there is a serious risk.

Just as experts argue over the best way of dealing with frostbite, so they have different views about how to try to survive an avalanche. There is no way of guaranteeing that you will not die. There are all sorts of avalanche patterns, from powder avalanches which drown you to slab avalanches which can break every bone in your body, or at least batter you senseless. You might start it yourself, or you might be engulfed in one started by another skier. Most likely it will start spontaneously and trap you in its path.

Avalanches can move frighteningly fast. You may have only a second or two to react. One possible reaction is to ski diagonally out of the avalanche's path. Another is to take your skis off and try to 'swim' on the surface of the snow. If you are sucked under the surface, try to keep a pocket of air in front of you by cupping your mouth and nose with your hand. When skiing off-piste wear an avalanche transceiver, never ski alone and if possible always take a guide.

Ueli Frei, President of the Mountain Guides Association in Grindelwald, who specialises in helicopter skiing and regularly rescues climbers stranded on the much-feared north face of the Eiger, remarks: "You have to respect the mountain. But for me there is more risk in crossing a busy street in London." But he admits that two of his most experienced colleagues have recently died in avalanches.

In general though, skiing statistics are encouraging. While the risk of minor injury - sprains, bruises, cuts - is high; major injuries - broken bones or torn ligaments - are much rarer, occurring once in every 200 days worth of skiing. For most recreational skiers, that is the equivalent of 20 years.

Incidentally, three per cent of injured skiers each year suffer from broken thumbs. But you can break a thumb even before you go skiing. Many people who practice on dry ski slopes sprain or break thumbs when they fall on the unforgiving plastic surface and sandwich a thumb between the slope and their body. But don't let that encourage you to give skiing the thumbs down. It's far too much fun. Just take it easy. And take care.