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May 2011

Tree Wells Are Trouble

With more skiers and riders heading off-piste, tree-well education can save lives.

Written by Allen Best | 0 comment

On a powder day, there are no friends. That saying is probably as old as the first ski lift, but it’s a dangerous wisdom, as has been demonstrated again this winter in a flurry of snow-immersion deaths. Altogether, six people had died as of mid-February, including one each in California and Colorado, plus two more each in Montana and British Columbia. Most of these involve tree wells.

Getting the most attention, because they occurred at the same resort and within a few days of each other, were those at Montana’s Whitefish Mountain Resort. The first victim, a 16-year-old exchange student from Germany, was unconscious but still had a faint heart beat after he was pulled out of a tree well in late December. He died several days later. Less than two weeks later, a 29-year-old probation and parole officer was found dead in another tree well, also in an off-piste but inbound area near the summit of the mountain. He had been reported missing two-and-half hours earlier after failing to reunite with friends at the end of the ski day.

The particulars of these separate tragedies broadly parallel a statistical profile of victims of what is clinically called non-avalanche related snow immersion deaths, or NARSIDs. About one-third of victims die with no tree nearby. But whether in tree wells or out, nearly all victims are young, male and were riding the snow alone during or shortly after a big storm, often close to a maintained trail. Over the longer statistical period, there is no difference between skis and snowboards. Hung upside down in a well, which at a place like Whitefish can be 10 feet deep, the victims are wedged by the tree and branches, barely able to move, and suffocated by the snow that has collapsed around them.

Education Is Key
Prodded by NSAA, ski areas have become more aware of the potential peril in recent years and have taken increasing steps to remind customers of dangers. And with more skiers entering the backcountry and even skiing the trees inside resort boundaries, tree-well and deep-snow immersions have become an area of growing attention.

Of the average 38 people who die annually at U.S. ski areas from all causes, including collisions, avalanches and the trauma from colliding with trees, the toll from snow immersions has averaged only 3.3 per winter since 1990, although edging upward to 3.8 deaths annually in the last decade. The figures do not include British Columbia, which has the highest single death toll of any state or province.

Like avalanches, the danger of immersions spikes during and immediately after major storms. But if cold persists, the snow can remain unconsol- idated for days, even weeks.

Again like avalanches, avoidance is the best precaution. If caught, virtually your only hope is to have somebody nearby. Plans to reconnect at the ski lift don’t qualify. People have died within 20 minutes, and perhaps less, after being inverted in tree wells.

Unlike avalanches, the danger of deep-snow and tree-well immersions was not broadly appreciated until relatively recently. Many snow professionals had their own brushes with danger, but dismissed them as freaky things.

But a few people began connecting the dots after Paul Baugher began hoisting a warning flag. A 30-year veteran of the ski industry, Baugher gave little thought to the first tree-well fatality at Washington’s Crystal Mountain, where he is director of ski patrol. “We thought it was a real fluke,” he says.

That was in the early 1990s. Then, a decade later, another one occurred. “It really made me start looking into this,” he says.

What’s Going On?
Baugher conducted an experiment in 2007 that showed just how difficult it was for somebody fully inverted into a tree well to escape without assistance. He recruited five snowboarders and five skiers among Crystal’s volunteer patrollers and suspended some fully inverted, as most victims are found, and others more horizontally. For safety purposes, he had a pulmonologist on hand with supplemental oxygen, emergency medical technicians, and snow shovelers. All volunteers had ropes tied to their waists.

“It was freaky to watch,” says Baugher. Several in shallow, horizontal positions managed to get out on their own. But all those who were inserted vertically in the wells wanted out before the two-minute time limit. Their faces as they emerged, says Baugher, were gooey, and some were turning blue.

Heavily-weighted downward pointing tree branches, the snow collapsing into the well, and finally the tree trunk itself left little or no room to move. Breathing itself was difficult. Indeed, some people in snow immersions suffer what is called positional asphyxiation, meaning the body’s contortion has blocked breathing.

The average age of snowboarders killed in deep-snow immersions is 23, and the average age of skiers is 32. Most of the victims are males, and most tree-well immersions are on moderate slopes of dispersed trees in off-piste areas that are often close to groomed trails.

Are snowboarders more susceptible to deep-snow immersion? That question partly motivated Baugher to dig into ski area fatalities, to ferret out the deep-snow immersions from the statistical pile. Nobody had done so before, and he remains the only one to do it now. The data from 1970 to 1990 were sketchy, but since then has become firm. Called to testify on behalf of a snowboard manufacturer in an Oregon, he testified that there was no correlation between binding types and fatalities.

“I told the jury, ‘Don’t buy into this,’” says Baugher. “Releasable bindings are not the answer. Having a partner is,” he says.

The increase in tree skiing makes the issue of tree-well immersion a growing risk-management concern. NSAA president Michael Berry ties the increase in off-piste access to equipment trends. “With the narrow-waisted 215-centimeter skis, it was the rare person who could enjoy the trees and have fun,” he says. Snowboards, and the new wider, shorter, and rocker skis, have changed that. “Even within the ropes, we are seeing people skiing areas that were only lightly skied 20 to 25 years ago. Now, they’re skied or boarded heavily. There are very few places that people don’t go now,” he says.

What Can Be Done?
Still, while the number of deaths has increased, there has been no explosion. Baugher says he’d like to believe his educational efforts—he has a website called and has spoken at many NSAA conferences—have reduced the death toll.

Canadian heli-ski operators were probably the first to understand tree-well dangers. “By the nature of the terrain we operate in, avalanche and tree wells are two of the major things that we’re watching at all times,” says Sarah Pearson, sale and media relations director for the Banff-based CMH Heli-Skiing, which has 10 heli-skiing lodges in the Purcell, Monashee and other ranges of the British Columbia interior. All guests, says Pearson, are instructed carefully in avalanches and tree wells. “When you are specifically teaching people about tree wells, the buddy system is incredibly important,” she says.

U.S. ski areas have been expanding their education efforts about immersion dangers. Prior to the two recent accidents, Whitefish had no educational component specific to tree wells other than occasional warnings in the snow report, says Donnie Clapp, public relations manger of the resort. It is now assembling one.

Many ski areas aren’t eager to talk about the dark side of their gladed, powder-rich skiing. Steamboat is an exception. With four tree-well fatalities in the last decade, including two in one year, the area has become aggressive in alerting customers to dangers.

The ski area operator reminds customers of the danger in its grooming reports, in flyers and at the ticket office. As well, a warning sign has been posted at the base of Morningside, a lift used to access backcountry-type terrain within the resort’s boundary.

Steamboat’s yellow-diamond sign, showing a powder track around a tree, has been adopted by some ski areas. Without referring specifically to that sign, Mart Petrozzi, vice president of risk management for Booth Creek Resorts, sees value in standardization of messaging to consumers, similar to the green, blue and black-diamond symbols.

Where’s the Risk?
Not all ski areas are equally at risk, however. Baugher has found none occurring east of the Rockies, probably because New England resorts just don’t get as much unconsolidated snow.

Type of trees can matter. Closely spaced, smallish lodgepole pine trees, such as have been most common in Colorado, are less likely to have large tree wells. Ditto for aspen trees. Larger coniferous trees with broad canopies result in a larger well around the trunk—and more danger of collapsed snow should a person slide into it.

But always there are exceptions: one death was caused by a tree, its top concealed by fresh snow. Below, however, was a sturdy prison of branches. Another unusual immersion—and inversion—occurred in Utah, where a snowboarder went headfirst into a snow bridge over a creek. He couldn’t pull himself up, and the board kept him from falling into the stream. He died the slow death of hypothermia.

Baugher, the self-described bell ringer of such dangers, does see evidence of growing awareness that he believes has reduced the death toll below what it would otherwise be. The easy part, he says, is that the same rules can be taken from the avalanche safety playbook. Stay in sight of your buddies, he says, they are your only hope. That’s the simple message that resorts must emphasize.

That simple message might have saved David Riddle, 49, a recent fatality. A 100-day-a-year snowrider for the last two decades, he was a free-spirited individual with training in physics and a head full of ideas. Venturing into the backcountry adjacent to Winter Park Resort in February with two companions, he became separated. When he was reported missing, at 4 p.m., it was likely too late. His body was found at 6 p.m., and although he was wearing a helmet, it didn’t really matter. What he needed was somebody see him plunge into the tree well and pull him out. Immediately.

Want to see what immersion looks like?  Check out “Snowboarder’s near-death caught on tape” at, or “Upside down in a Tree Well,” in three parts, on YouTube—where there are several other tree-well immersions caught on video.