A Heuristic Sense of Snow

By Peter Kray

Heuristics are the mental shortcuts we take to make decisions. Right or wrong, they are the reasons we duck at the sound of gunfire, or start bragging even louder when an especially attractive someone enters the room. Often instantaneous educated guesses, such as recognizing who might be going outside for a safety meeting or who in the bar is in the best shape to ask for a ride home, they are a gamble the same as playing cards or predicting the weather, and quite often the conclusions they lead to are dead wrong.

That was the case this winter, when a near- record number of people in position to the make the best bet on the relative danger of their local snowpack were killed by avalanche. In an already legendary season deep in hyperbole — record snowfall in the mountains of Montana and Wyoming, record at-resort deaths in Colorado, record faceshots, fat skis sold, etc. —  avalanches had claimed 34 people in the US by April 10th. That’s one dead ski buddy short of equaling the modern record of 35 US avalanche victims set in the winter of 2001-02 — and this with the deep spring backcountry touring season just begun. Especially troubling is the fact that a lot of those skiers, snowboarders, snowshoers and snowmobilers died traveling in their home hills and when they died, heuristics, or more appropriately, “heuristic traps,” were usually to blame.

“Human beings have never made decisions logically,” says Bruce Tremper, director of the Utah Avalanche Center. “It’s because we all have short memories, me included, and make decisions based on short-term evidence. In the Wasatch, the snowpack has been stable with warm air and high freezing levels — a maritime snowpack — for the last three to four years. But this year we’ve had the classic weak, faceted snow layer, which has been easily triggered. So when I get all the media calls asking why this is happening, I tell them what’s unusual is that the snowpack is usual this year.”

In his article on the subject, Evidence of heuristic traps in recreational avalanche accidents, Avalanche researcher Ian McCammon asserts that familiarity is one of the four deadly sins when recreating in slide-prone terrain. It is the reason why someone neglects to dig a snowpit and then gets slid skiing a line that they have safely skied dozens of times. The other three most common traps are: social proof (“that dude skied it”), commitment (“we hiked for four hours”) and scarcity (“it’s the last clean line”).

But anyone who has ever been in a group where nobody checks beacons because “everyone here is an expert,” or seen their buddies start blindly hucking off cliffs and cornices in an effort to impress the good-looking girl from the British ski club, or skinned five miles behind some ridge hippie stoned on blonde hashish to reach the Shangri-La Chutes, knows that heuristic traps are easily sprung in the backcountry, and complacency is the winter traveler’s greatest crime.

“Most of the victims this year seem to have been pretty savvy skiers and riders, and a couple were even off-duty ski patrollers,” says Dale Atkins, a snow safety consultant and former avalanche forecaster for the Colorado Avalanche Information Center. “In essence, these are people that you would like to think would have known better.”

The epic snowfall proved to be too deadly a variable Atkins says. “They weren’t prepared for such an exceptional winter. They were acting in a way that is good enough for most winters, but not for a year when many regions saw an entire winter’s snowfall in just two months.”

Atkins, who first published his own findings on heuristic traps in Snowy Torrents, the professional compendium of US avalanche accidents, in 1996, says that surprisingly, skiers who take avalanche courses are more likely to fall into a heuristic trap. He says, “A majority of avalanche victims have had some formal snow safety training, and one third have had a lot of training, but still allowed themselves to get into trouble. A lot of it goes back to the fact that people are not very good at assessing personal risk.”

And, as skis get fatter, pressure on in-bounds powder increases and lift-served access to the backcountry becomes more commonplace, Atkins foresees the emergence of a new heuristic trap: thinking that in-bounds snow can be used to predict the backcountry experience.

“Snow’s not color-coded for risk — it’s all white,” Atkins says. “Which is why sometimes it’s very hard for people to understand how that quarter-inch boundary rope is all that separates them from a relatively controlled environment and the wild west.”