Avalanche fatalities related to size of group, study finds

When it comes to avalanche safety, a recent study says solo travelers or pairs are less likely to be caught in a snow slide.

The study’s findings are counterintuitive to conventional wisdom about traveling alone in the winter backcountry on skis, snowshoes or a snowmobile.

“We always encourage people to travel with a partner because that gives you a better chance of survival if something happens,” said Alex Marienthal of the Gallatin National Forest Avalanche Center.

The study may reveal a simple component of human nature.

“When I go out in winter by myself, I ski pretty darn conservative,” said Scott Toepfer, mountain weather and avalanche forecaster at the Colorado Avalanche Information Center. “I don’t want to get caught in avalanche terrain.”

The study was published in the March issue of the research journal “Wilderness & Environmental Medicine.” The researchers used Swiss and Italian backcountry statistics to compare group size with avalanche injuries and fatalities. Even though traveling in larger groups is a less common mode of recreation, those individuals were more likely to be caught in an avalanche, the study showed.

“Although the most common group size was two in both the usage and the accident datasets, larger groups had relatively more accidents,” according to a synopsis of the study. “The highest risk was found for groups of six or more people in both the Swiss and Italian datasets. For example, while groups of six or more people made up only 10 percent of all groups, they accounted for 23 percent of all accidents.”

The reasons the study cited for the increased risk include:

• –A large group creates a higher load on the snow cover.
• –With more travelers on the snowpack, there’s an increased probability one of them will hit a weak spot in the snow and trigger a slide.
• –The slower decision-making process of groups could increase risk.
• –There are challenges in communication with more people.
• –There may be a heightened “risk-appetite” because the group could create a false sense of security for individuals.

Marienthal said he sees communication among a large group as one of the biggest problems.

“Communication and group management in general is a challenge,” he said. “The task of only exposing one person to avalanche terrain becomes more difficult with more people.”

Toepfer agreed that riders may be more willing to take a risk when they are in a group.

“There may be a little bit of competition to grab the nicer line that probably contributes to that,” he said.

Colorado has already had one solo snowbiker and a lone climber killed in avalanches this season and three riders injured while alone.

“It does seem to be a bit more of a problem for us this year,” Toepfer said.

In the same publication, another article noted that Colorado has seen an increase in avalanche deaths among snowmobilers and snowboarders as the interest in those sports has climbed, and a decrease in deaths of backcountry skiers.

Snowmobiling accounted for 23 percent of all deaths, increasing by about 7 percent per decade over the past 60 years since record keeping began. The snowboarder fatalities has climbed about 2 percent per decade. The majority of those fatalities, 86 percent, were among men. The mean age of avalanche victims was 29, plus or minus about six years.

In the Idaho Panhandle, snowmobiling accounts for seven of the 10 avalanche fatalities since 2000.

However, although more people in different groups are heading into the winter backcountry, there’s been a decline in the percentage of fatalities among winter users. That could be due to better education among those recreationists.

Of the 149 winter backcountry users surveyed in Utah’s Wasatch Mountains and Wyoming’s Tetons for a 2014 study, 77 percent carried basic avalanche safety equipment like a transceiver, shovel and probe, according to a September study published in “Wilderness & Environmental Medicine.”

Fewer carried high-end gear like an AvaLung or avalanche air bag because of the expense of the items. Air bags, which are meant to keep victims atop the snow, cost more than $1,300.

The Teton-Wasatch study also found that snowmobilers and snowshoers were less likely than backcountry skiers to have taken an avalanche safety course.

Across the U.S. this year, at least 25 avalanche fatalities have been recorded so far, up from 11 last year, according to the Colorado Avalanche Information Center. Wyoming, Colorado and Alaska have each recorded four fatalities this winter.

According to the information center, the worst of the past 17 seasons was the 2002-03 winter when 58 people died in avalanches, six of which occurred in Montana and nine in Wyoming.