When adults die on thrill-seeking adventures, the people who knew them grieve, but the broader community often does little more than shrug. As adults, the thrill-seekers could be trusted to make a very personal decision weighing the adventure's benefits against its risks. The mourning is a private matter.

When children or teenagers face life-threatening dangers in the name of education, the aftermath of an accident is different. The tragedy is a public one. Young people are not responsible for life-and-death decisions; the community at large has a role to play, along with the parents and teachers involved, in determining what is an acceptable risk.

So it is with the deaths of seven 15-year-olds asphyxiated by an avalanche while on a school skiing trip to the backcountry of British Columbia. As we grieve, for the students and their parents, for their friends at Strathcona-Tweedsmuir School south of Calgary and the communities in which they lived, we must also, while avoiding the simplistic criticisms of hindsight, search for ways to avoid similar tragedies.

On Saturday, the day of the avalanche, the Canadian Avalanche Association warned in its bulletin that the risk was "considerable." Roget's Thesaurus lists these as synonyms: sizable, substantial, large, big, great. So there was a credible warning beforehand. Exposing 15-year-olds to this "considerable" risk is unacceptable. Why did the trip leaders not decide to sit Saturday out?

About those leaders: How expert were they? What training, certification and experience did they have? Why did they not lead the group up the relatively protected shoulder of Cheops Mountain, rather than through the flatter parts of the valley, where they were more vulnerable to an avalanche?

One possible answer is that overconfidence set in because the school had made the trip so many times. Rogers Pass is an easy weekend excursion from Calgary, and 90 minutes from the Trans-Canada Highway; no helicopter is needed. It is the backcountry at your back door.

Tony Macoun, the head of the school, said on CBC Radio yesterday that the school has been doing backcountry ski trips for 20 years. To what extent did this record of success, the accessibility of the location, even the "avalanche training" given the students beforehand (how to dig out the buried, for instance) provide a false sense of security, and perhaps obscure the risks?

Saturday's warning was not the first that Strathcona-Tweedsmuir would have been aware of. Twelve days earlier, seven adult skiers were killed by an avalanche 65 kilometres away. (The risk was listed as considerable that day, too.) Word was already out that this may be the worst season in 30 years. Warm temperatures and a small early snowfall made for an unstable base. Heavy snows more recently have piled on that base.

For young people growing up in a mountainous area, it makes some sense to teach by immersing them in the natural environment. Beyond that, what was the objective? Senior principal Glenn Odland said yesterday such trips help "develop their character and their ability to master challenges."

And maybe they do. But an avalanche can be totally unpredictable. As Canadian snowboarder Ross Rebagliati said last month of his own backcountry experiences: "Everyone knew there could be a slide at any time." Challenging the elements is one thing; simply braving the odds is quite another.

Teenagers do not, as a rule, have the maturity to make life-and-death decisions for themselves. They may feel invincible. They may worry more about losing face by avoiding risk than they worry about dying. And all of them are told from the time they are small that as long as they are in the care of adults, those adults will not knowingly expose them to deadly harm. Thus, 15 year-olds are not allowed to drive, drink or join the army.

Becoming independent requires some assumption of risk. That is the process of growing up. Toronto's school board, failing to understand this, demolished its playground equipment in 170 schoolyards three years ago without any statistical evidence of dangerousness. Hockey, Canada's game, exposes boys and girls to the risk of serious spinal-cord injuries, yet the game goes on.

An inquest would help Canadians decide how much risk is too much when young people are involved. A moratorium should be called on all school backcountry trips to avalanche-prone areas, until an inquest can produce some measured responses, out of the heat, and grief, of the moment.