The first thing I realise as we venture out of the patrol headquarters at the top of Cairngorm ski station, is that a 70mph wind isn't just an irritant which has caused all the ski lifts to close - it is also an awesome force vicious enough to knock me clean over.

"If you can ski in Scotland," grins Dr Mike Langran, Cairngorm's ski patrol doctor as he watches me clatter back upright on my skis, "then you can ski anywhere!"

The wind howls around our heads mockingly, spitting sleet in our faces.

"Another good reason for wearing this!" he jokes, rapping his knuckles on his helmet. "It keeps you warm!"

People need to know that a helmet doesn't make you invincible Dr Mike Langran, International Society for Skiing Safety

Dr Mike, as he is known in these parts, never hits the slopes without a helmet and whenever he has to tend to an injured boarder or skier who is not wearing one, he encourages them to try one out.

Around 10% of those he treats on the mountain-side have sustained some degree of head injury - but Dr Mike is not an advocate of making helmets mandatory on the slopes.

He is also president of the International Society for Skiing Safety and, having studied ski accident statistics from around the world, he knows the risks of sustaining a head injury are small.

He is also interested by the fact that despite a 40% increase in recent years in the number of skiers and boarders wearing helmets in Scotland, there has been no reduction in the number of people who have sustained head injuries.

Media playback is unsupported on your device Media caption Gregor Samuels: 'I'd have been dead if I wasn't wearing my helmet'

"There is some research that indicates that helmet wearers take more risks," he says.

He indicates down the slope with his ski pole, although it's now so foggy I can't see more than a few feet in front of me.

"I've certainly seen boarders and skiers doing some crazy things on this mountain which I'm pretty sure they wouldn't be doing if they weren't wearing a helmet.

"People need to know that a helmet doesn't make you invincible."

Left in a coma

The snow beneath our feet rasps suddenly and a border in a bright yellow jacket shoots past us, his board scraping the top layer of ice that's frosted onto the hard packed snow, his teeth flashing in a broad smile as he expertly descends the slope.

He is 17-year-old Gregor Samuels, a member of the British freestyle boarding team, only just back on the pistes after a badly executed jump last year in Colorado left him in a coma for four weeks and in hospital for four months.

Helmets and injuries The overall risk of injury from skiing or snowboarding is much lower than most people imagine ( one to two injuries per 1,000 skier days and two to four injuries per 1,000 snowboarder days).

A 2011 British Medical Journal study from the University of Innsbruck suggested helmet use reduced head injuries by 35% in adults and 59% in children under 13.

The same study showed 74% of head injuries occurred when skiers hit their head on the snow, 10% when they collided with each other and 13% when they collided with fixed objects.

A study in Scotland from 1999 - 2008 found head injuries accounted for just under 15% of all boarder and skier injuries.

"The doctors said I'd have been dead if I wasn't wearing my helmet," he tells me when we meet up in the warmth of the top station restaurant.

"If any of my friends aren't wearing their helmets now, I won't take it from them - I make them put them on."

He hands me a photograph of himself in the coma in which he is slumped lifeless in a hospital cot, horrific tubes protruding out of his head.

He says he can only vaguely recall being transferred to the hospital in an ambulance.

But his mum Suzanne interjects gently: "No Gregor. That was when you were taken to the rehabilitation unit. That was over four weeks after you fell."

Research shows the under 16s are far more likely to have an accident than adults. And in Italy and Austria, it's now compulsory for children to wear a helmet on the slopes.

Discount offer

Stories like Gregor's have inspired the UK travel insurer, Essential Travel, to offer a 15% discount to any one heading for a winter sports holiday who agrees to wear a helmet.

Dr Langran on head injuries The precise nature of head injuries seen will vary from resort to resort depending on factors such as user population and the particular features, such as presence of trees, etc. The vast majority are fairly minor, such as bruising, abrasions and lacerations from impact with objects such as ski poles and ski lift bars, or the snow surface itself. More serious injuries usually occur as a result of collisions with trees or other skiers/boarders. These sort of injuries tend to include loss of consciousness, concussion, skull fracture and intracranial bleeding/swelling (in isolation or in combination)

"We're the ones who see the claims come rolling in," says marketing manager Nina Montgomery.

"And we see the dangers and difficulties our clients are coming up against on the slopes, so we want to convey to the public what we're seeing and we want to advise them of the precautions they could take so they don't have a horrible end to their holiday."

There are limits to the degree of protection even modern helmets can provide, and many collisions - either into other skiers or into trees or pylons - result in forces that may exceed these limits.

France, the European country with one of the lowest rates of helmet use, is extremely conscientious about placing signs all over the slopes warning skiers to slow down.

Media playback is unsupported on your device Media caption Dr Mike Langran talks about the risks of not wearing a ski helmet

But watching scores of people hurtle down the mountainside at Val d'Isere, it became clear that few people were taking heed.

"It's quite difficult for us," says Renaud Lobry, head of the Val D'Isere ski patrol team.

"In France we have to protect skiers' liberty and speed is a real problem; it's a factor of danger, of collision and accidents - but we are not allowed to do anything - we cannot take their lift passes or tickets - we can just give advice, and not much more than that."

Even experts in danger

My own instructor, Pat Zimmer, is proof that anybody can be at risk.

A French former downhill champion he had always skied with an idiosyncratic, and very becoming, bobble hat.

Then one morning last December on a quiet slope, an out-of-control skier smashed into him and sent him flying. He landed heavily on his head, prompting a serious brain haemorrhage.

Quick work by neurosurgeons saved his life, and he is now back on the slopes - accompanied by a gleaming white helmet.

"My advice?" he says, "Clunk, click, every trip! And never leave home without it!"