Just how safe are you on the slopes? Actress Natasha Richardson's death in a skiing accident at the Mont Tremblant ski resort in Quebec, Canada, has revived questions about the safety of alpine skiing.
Doctors say numbers are hard to come by, but studies suggest that while skiing overall has become safer because of better equipment, the number of deaths -- mostly from severe head injuries -- seems to be on the rise.
"We are concerned," said Dr. Charles Tator, a Toronto neurosurgeon and the founder of ThinkFirst Canada, a safety group. He headed a 2007 study in which he and three colleagues looked at reports of ski-related injuries around the world.
"The overall number of injuries of all sorts -- broken legs, broken arms and so forth -- is going down," he said. In the 1970s, it was estimated there were five to eight injuries per thousand days people spent on the slopes; today, Tator says, it has dropped to 2-3.
"But to the best of our ability to find out," he said, "the numbers of deaths are going up."
Most of those injuries, he said, are to the head and neck. He blamed many of them on risk-taking -- skiers who try aerial stunts or disregard other skiers.
Tator said skiing statistics are not regularly compiled. There is far less information on alpine skiing worldwide, he said, than on sports such as football in the United States or hockey in Canada.
Tator and his colleagues, writing in the journal Injury Prevention, examined data from 10 countries. They found that head injuries comprised 15 percent of injuries sustained by skiers in 2007, compared with 12 percent in 1993.
Helmets Are a 'Mixed Blessing'
They also said that wearing a helmet can reduce the risk of serious brain injury by 22 percent to 60 percent.
Richardson reportedly took a tumble on a beginner's slope, and did not think, at first, that she had done herself any harm. Doctors not involved in the case say it is possible she had a pre-existing condition that made her vulnerable in a fall. Her family, requesting privacy, has not released medical details.
A spokesperson for the Canada resort where Richardson fell said she was not wearing a helmet and helmets are not required on the mountain.
Experts, however, caution that helmets are not the be-all and end-all.
"Helmets are a mixed blessing," said Dr. Douglas Hill, a Denver emergency physician, member of the American College of Emergency Physicians and former ski patrol member.
He encourages skiers to use helmets but said that while they help, they work best when skiers are traveling up to 15 mph. Some skiers, thinking they are invincible with a helmet on, may travel faster and take more risks, thereby putting themselves in more danger.
"It's a safe sport. But you have to be careful," he said.
Hill said he had also seen more head injuries come through his emergency room in recent years.
Still, the skiing industry maintains that though celebrity accidents often renew conversations about safety, skiing is no more hazardous than in the past or than for other sports, such as swimming and mountain biking.
Skiing: Safer Than Biking, Swimming
"Sometimes when it's a high-profile person, it draws a lot of media attention and along with that some questions as to the safety of the sport. But if we look at the average, it remains pretty stable," Troy Hawks, communications manager for the industry group National Ski Area Association, told ABCNews.com. Despite some seasonal variation, the 10-year average, he continued, has not changed significantly.
"Of course, we'd like to see zero. But of course accidents do happen," he said.
Each year, the NSAA gathers and publishes accident reports from ski patrol organizations, ski resorts and other sources across the country.
In the 2007-2008 season, 41 serious injuries took place at U.S. ski resorts, compared with 40 in the 2006-2007 season and 57 in the previous season.
The 10-year average, the group said, is 43.6 serious injuries each year. The 10-year rate of injury is .68 injuries per million skier/snowboarder visits.
8 Millon Skiiers; 43 Deaths Per Year
The fatality figures have been similar, Hawks said.
Fifty-three skiers and snowboarders died accidentally on U.S. slopes in the 2007-2008 season, compared with 22 deaths in 2006-2007 and 39 in the season before. An average of 39.8 skier and snowboarder fatalities have occurred on the slopes each season over the past decade. And the 10-year fatality rate is .88 per million.
More often than not, Hawks said, younger males are injured or killed on the slopes.
Hawks said that although the argument could be made that advances in technology allow skiers and snowboarders to feel as if they have more control at faster speeds, there is "just no data showing that there's been any increase in injuries."
Terrain parks that allow skiers and snowboarders to jump and perform acrobatics are relatively new to resorts, but, through signage, mountain ambassadors and radar guns that let guests know how fast they are traveling, more resorts proactively encourage safety.
Slopes Are a 'Set-Up for Collisions'
But safety advocates argue that these measures have not sufficiently kept pace with advances in technology, such as shaped or parabolic skis, and grooming techniques that have increased the average speed of skiers.
"They've been clocking the skiers. It's not unusual for a skiing accident to occur when one person hits another at 40 to 50 mph," said Dr. Daniel Gregory, a California physician and founder of the SnowSport Safety Foundation and the California Ski & Snowboard Safety Organization.
Skiers travel 10-15 mph faster than they did about a decade ago, he said. And, because resorts have been successful at drawing more people to skiing, the slopes are crowded with people of varying abilities.
"That's a set-up for collisions," he told ABCNews.com.
Gregory founded his organizations after his daughter Jessica died skiing at Lake Tahoe in 2006 and is involved in a lawsuit related to her death.
While some situations may not be avoidable, he urged that more transparency and emphasis on prevention and safety is needed.
Richardson, 45, and married to the actor Liam Neeson, reportedly fell while taking a skiing lesson at Mont Tremblant, Quebec, in the Laurentian Mountains north of Montreal. She died Wedesnday from her injuries in a New York hospital, a spokesperson said.
Some other prominent people killed or severely injured on the slopes in recent years:
Sonny Bono, the singer who first gained fame as part of the husband-wife group Sonny and Cher, later became a Republican congressman from Southern California.
He was killed after he hit a tree at Heavenly Ski Resort near South Lake Tahoe, Calif., Jan. 5, 1998. His epitaph is the title of one of his most popular songs: "And the Beat Goes On."
Michael Kennedy was the sixth of 11 children of Robert F. Kennedy and his wife, Ethel. A lawyer by training, he helped his brother Joe Kennedy run Citizens Energy Corp., a nonprofit organization that supplied heating oil to people who could not afford it.
Kennedy died in a 1997 skiing accident near Aspen, Colo.
Princess Caroline of Monaco was skiing at an exclusive ski resort in the Austrian Alps, in 2001, when a skier crashed into her while she was with an instructor. The princess, who is the eldest daughter of American film actress Grace Kelly, was airlifted to a private clinic where a keyhole operation repaired her torn knee ligament.
Supermodel Christie Brinkley hurt her back during a 2006 ski trip in Aspen, Colo. The CoverGirl cosmetics model reportedly noticed something was wrong after she fell while skiing. A doctor's visit revealed that she was very close to severing her spinal cord, Brinkley told "Extra." In February 2007, she underwent surgery to address the problem.
John McWethy, the chief national security correspondent for ABC News died at 61 after chest injuries sustained in a 2008 skiing accident. After serving as the nework's chief national security correspondent since 1984, McWethy had retired to Boulder, Colo., with his wife.
Dieter Althaus, 50, is a German politician, the president of the central German state of Thuringia. On Jan. 1, 2009, he was skiing in Styria, Austria, when he reportedly wandered from an expert run onto a beginner's course and collided with a 41-year-old woman, Beata Christandl.
He was wearing a helmet, but she was not. She later died. Althaus, who was seriously injured, was convicted of involuntary manslaughter. He was fined 33,000 euros (about $41,000), and ordered to pay an additional 5,000 euros to Christandl's husband.
"Depending on whose numbers you use, there are 8 [million] to 10 million regular skiers in America," said Greg Ditrinco, the executive editor of Ski Magazine in Boulder, Colo., "and the number of serious injuries and deaths is low.
"In the last five to eight years skiers have been using shorter, wider skis," he said. "The gear revolution has put people on terrain they would not have been on 10 or 15 years ago. They're skiing more of the mountain."
"But we've done stories over the years about how safe it is -- how it's safer than riding a bike or swimming, things like that," he said.