Near Miss – An Avalanche Survival Story – Broken Thumb Couloir – Grand Teton N.P. (01.26.20)

First and foremost, it is with a heavy heart that I solemnly offer my condolences to the family of Matthew Brien, a 33 year old Jackson local taken by the mountains far too early. 2021 was undoubtedly one of the toughest years for snow stability in the mountain west. February was the worst – haunted by a one-two punch of persistent weak layers from unseasonably early September snowfall and a thorough January thaw. Strong winds and unrelenting snowfall, up to thirteen feet in two weeks (mid-February), put incredible stress on these layers and created a deviously tempting but dangerous snowpack. The point of this article isn’t to delve into the weeds of snow science or discuss Brien’s incident, but instead to tell the story of my own experience triggering and barely escaping an avalanche in the identical spot Brien made his final turns. I hope to highlight the many poor decisions, few good decisions and one ultimately life-saving decision our party made in the Broken Thumb Couloir, in hopes that all backcountry skiers can take away a few nuggets for safer adventures.

The Broken Thumb

Janurary 26, 2020 started like any other Grand Teton National Park ski mountaineering adventure would. There was lots of coffee, overflowing excitement and a bit of sleep deprivation. Being my birthday, the crew let me choose the objective. The Broken Thumb Couloir on the north side of Peak 25 Short, a short but highly technical line with a mid-route rappel had been on my radar for some time. The snow conditions weren’t perfect, but they weren’t damning either – with cool heads I figured we could at least “check it out.”

I made a swipe at the Broken Thumb once before, but unfortunately mis-navigated amidst an intensifying storm. My partner and I got stranded above a monster cliff band, couldn’t re-ascend due to dangerous avalanche conditions and had to employ two emergency rappels to reach the proper apron of the Broken Thumb some 200 feet below. (looker’s left of the line in the photo above). Lucky for us there were plenty of large trees to use as anchors – otherwise, without any spare rack to bail, we’d have been in a sticky situation. We had no pictures or maps of the line, and made the fatal mistake of following past skier tracks. As it turns out, those “other skiers” were only minutes ahead of us, actively discussing their own emergency plan when we descended above them. Working together as a group of five we all returned home unscathed – dangerously close to an epic – or worse.

Back to 2020. After two magnificent “top-to-bottom” powder laps on the moderate eastern slopes of 25 Short, our trio gathered atop the summit one last time. 12-18 inches of new light snow had fallen overnight, creating an epic canvas for amazing turns. We were having an amazing day and parlayed one last time to discuss our options. The time was 2:00PM, a little late for a technical descent with the sun setting between 4:00 and 5:00, but we had mercilessly lugged ropes, harnesses, ice axes, crampons and rappel gear to the top of a 10,000 foot mountain – to what, just ski mellow powder? Just to the north of our lunch spot was the entrance to the Broken Thumb Couloir, the crowning jewel of our outing. The daily forecast from the Bridger-Teton Avalanche Center warned of wind-slab avalanches on northerly aspects, with increasing danger as new snow continued to fall. The afternoon hazard rating increased from “low” to “moderate” for higher elevations. We weren’t naive or ignorant – we knew the risks and had spent the entire day evaluating the snow-pack, digging pits and debating whether or not to roll the dice. As a group we were well-seasoned in steep Teton skiing, and the Broken Thumb was well within our capabilities. In hindsight, we just toed the line too damn close, lured by an intoxicating potion of adrenaline, birthday excitement and deep powder.

The turns above the Broken Thumb were stable, dreamy and silky smooth.

Approaching the Broken Thumb involves a few hundred feet of moderate lightly-treed skiing – an epic spectacle of pristine powder turns this afternoon. Glades are a very easy place to loose bearings but drawing on my previous adventure I guided our team flawlessly. After a few hundred feet the dense pines terminate in a blatant fork marked by a gigantic rock pillar rising dramatically from the snow. To the right (east) was the dead-end apron I wandered onto the year prior, and to the left (west), a steep gully leading to the entrance of the Broken Thumb Couloir. I had done my homework thoroughly, and this time I was confident. We veered left but abruptly halted at the sight of a wind loaded headwall, clearly flagged by slightly textured and bulging snow. Two of us sunk into a grove of trees as the other volunteered a ski cut, instantly shattering a small avalanche into steepening terrain. While big enough to knock a skier off balance and alarmingly reactive, the wind-slab lost momentum quickly and failed to propagate into a larger slide. The crown was about eight inches, 20-25 feet wide and ran for about 100 feet before dissipating into slough. The way we saw it, our avalanche mitigation tactics worked seamlessly. We were able to identify a hazard, safely trigger a controlled event and move through the terrain unharmed. We talked briefly about re-ascending, but by now we were at least 1,000 feet into the beast. In fresh powder, a retreat would have meant at least an hour of breaking trail through thigh deep snow. Ultimately we decided to forge on, armed and ready to dispatch any other threatening wind-slabs.

My partner in the entrance “gully” just below the first avalanche trigger.

The powder between the gully and couloir was excellent, light and dry without any signs of wind-slab danger. The snow didn’t even flinch, utterly un-reactive. We regrouped in the final cluster of trees before rounding the corner of the Broken Thumb. The couloir was obviously plumped with fresh snow, however, there were no obvious signs of wind slab development, no rippled texture or abnormal loading, and certainly no crowns. Frankly, the 45 degree slope looked too good to be true, velvety smooth and chocked to the brim with birthday powder. From our vantage point the couloir doglegged hard to the northeast, and we couldn’t actually eye up the constriction. From our safe zone to the rappel anchor we would be skiing down several hundred feet of “no-fall”, zero avalanche tolerance terrain – a high risk terrain trap. Drunk on adrenaline I dropped in for the ubiquitous ski cut I had done countless times before – a high paced and precise traverse between two safe zones to attempt to propagate an avalanche – and boy, propagate an avalanche I did. Ski cuts so rarely produce results they can become “run of the mill”, but my decision to ski cut the Broken Thumb is the only reason I am here writing this article today.

A shot of the avalanche breaking beneath my skis from a GOPRO, with the fracture line drawn in black.

The sound of the avalanche breaking was bone shattering, like the blast from a 12 gauge shotgun, no exaggeration. Suddenly the entire slope was melting away, with a shooting crack stretching from the wall of the couloir to the top of the ridge several hundred feet above. “Slab!” I shouted as loud as I could, sliding off the flank and beaching my skis into a small rock island, my pre-identified safe zone. I then watched in disbelief as thousands of tons of snow ripped by me like a dam break water surge, all while I clung to a small pillar of granite the size of a coffee table. Within seconds the speed of the snow accelerated well past what had to be fifty miles per hour, continuing for many seconds, thrashing the walls of the couloir and scraping them dry like a pipe cleaner. The once serene snowscape was now a war-zone, with deafening sounds louder than a subway station inbound train. “I’m safe. I’m safe!” I yelled to my partners above. They reported hearing my voice in disbelief. They thought I was dead.

After a short regrouping we composed ourselves just enough to hack turns through the now completely safe but utterly mutilated couloir, finding the rappel station, dropping over the mid-route cliff and escaping into Avalanche Canyon below. As I rappelled the crux I was blown away to see the damage beneath my ski boots. The impact of the first slide cascading over the choke produced a deeper and more insidious avalanche in the lower couloir (16-20 inch crown) that ran nearly a thousand feet to the canyon belly. Flooded by shock and trauma I didn’t take any pictures below the rappel, so I can’t approximate the size of the debris pile – but it was big. Even if I’d survived a ride through the cliffs, a burial would have been almost certain and very deep. We returned to our cars a sloppy mess of stunned and grateful with very few words. We all knew what happened, and didn’t need to beat the dead horse today. I was just happy to see the sun set on my 25th birthday.

A Quick Analysis

What went wrong? Well, clearly lots of things went wrong. There were also a few things that went right. Without a doubt the decision to enter the couloir in the first place was wrong, but the ability to key into intuition, identify a safe zone and preform a ski cut saved my life. The American Alpine Institue offers the acronym ALPTRUTH to assess dangers of backcountry ski terrain. In a survey of over 100 incidents, approximately ninety percent involve three or more of these warning signs. A yes to any questions indicates a point for danger (red), and a no indicates a point for safety (green). Let’s take a look at my Broken Thumb experience through the ALPTRUTH lens:

  • A – Avalanche. Has there been any recent avalanches on similar aspects?
    • Yes, we triggered one just above the couloir on the same aspect.
  • L – Loading. Has there been any precipitation loading in the past 48 hours?
    • Yes, between 1-2 feet of fresh snow.
  • P – Path. Will you cross or travel in an avalanche path?
    • Yes, virtually all couloirs are avalanche paths.
  • T – Terrain Trap. Are there gullies, trees or cliffs that could increase the severity of an avalanche?
    • Yes, a large cliff in the middle and doglegging walls.
  • R – Rating. What was the avalanche danger rating for the day? Was it considerable or higher?
    • No, the rating was moderate.
  • U – Unstable snow. Have you heard any cracking or woomphing, signs of instability?
    • Yes, we triggered a small avalanche above, indicative of instability
  • TH – Thaw. Has there been any warming due to sun exposure or temperature?
    • Yes, despite the cloud cover the temperature had warmed significantly since the snowfall.

With three or more yes answers being indicative of high avalanche danger, our score of six points amounts to seriously risky business. What were the factors that lead us to venture into (and continue down) the Broken Thumb despite the obvious warning signs?

  • Excitement and anticipation
    • By hauling ski mountaineering equipment to the summit, the 26th being my birthday and two phenomenal powder runs beforehand we were supercharged with an influx of distracting excitement.
  • Top-Down Line
    • The Broken Thumb is a “top down” line, meaning we were unable to assess the snow in the couloir on the way up, having to use the NEARBY BUT NOT AT ALL SIMILAR east facing aspect as our barometer for snow stability. In my opinion, “top down” lines are usually far more dangerous than “bottom up” lines where you ascend the same path you’re going to descend, simply because of the unknown factor.
  • High Commitment Line
    • The Broken Thumb is a highly committing line. We didn’t reach the technical portion of the descent until we had skied about 1,000 vertical feet of deep powder. To reascend would have taken the rest of our precious daylight and incentivized us to continue despite obvious warning signs.

Lastly, there were three key safety precautions we employed that despite our poor decisions, allowed us to return home safely. These were:

  • Constant evaluation.
    • We were on constant vigil for indications of snow density changes, wind effect and other signs of potential avalanches. We successfully spotted both problematic trigger points before skiing onto them, and successfully propagated avalanches before we skied on top of them.
  • Avalanche mitigation.
    • Ski cuts are a tried and tested tool for testing a dangerous snowpack before fully committing to a line. Though not foolproof in danger assessment or safety, a sharp traverse from safe zone to safe zone above a problematic area allowed us to trigger both a small and large avalanche without getting trapped in either.

      Note: because we were in an extremely remote and “top down” zone, we were 99% certain no skiers were below us. To ski cut a popular slope or “bottom up” line could put other parties in jeopardy. Read more professional advice about ski cuts before testing in the field!
  • Avalanche safety plan.
    • Similar to a fire escape plan for your home or business, an avalanche escape plan involves hashing out a protocol with your partners BEFORE a crisis is encountered. Obviously, the best choice is to avoid dangerous situations entirely. However, in this scenario, we recognized the danger and identified safe zones for all parties. My partners stayed out from the avalanche path, protected by a very tight grove of trees removed from the chute itself. I located a well-protected rock outcropping to escape the slope in the event an avalanche broke. Both safe zones worked flawlessly because we took the time (and had the knowledge) to make an effective plan.

Additional Resources and References

More information can be read about ALPTRUTH at:

More information can be read about our incident at:

More information can be read about Matthew Brien’s incident at:

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The information in this article is provided strictly for informational purposes.

If you decide to attempt anything you read about in this article, you are doing so at your own risk.

2 thoughts on “Near Miss – An Avalanche Survival Story – Broken Thumb Couloir – Grand Teton N.P. (01.26.20)

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  1. I’m sorry I cannot find the name of the young man who wrote this article otherwise I would have made my comment directly to you. My sister came across this article accidentally and shared it with me – I am Matt Brien’s mother. We are approaching a year since we lost our son and are still struggling with the agony of moving on in life without him. I am so happy you are safe and alive and hopefully dialed back your extremely risky lines after this. You were so lucky to get another chance so please don’t make it for naught. Thank you for not making Matt sound irresponsible or ignorant of avalanche safety – he and his friends did all of the research you did and went over everything again the morning they headed out. I hope every skiier and snowboarder that read your article thinks twice about if the stoke or the tale of telling his adventure later is truly worth his life. Thank you for raising this awareness.
    Gail Brien


    1. Hi Gail, this is my website. I am the one that wrote this article. Thank you for your gentle words, and I am so very sorry for your loss. I never got a chance to meet Matt, but I have ski partners that knew him personally and spoke very highly of him as both a friend and adventurer. I’m glad you felt this article was an accurate representation of the incident, and I hope it continues to spread awareness through the years to come.


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