Many picture dramatic events, such as avalanches, as the main danger faced by skiers and riders on the slopes. However, within in-bounds terrain, tree wells have actually been far more dangerous in the United States. According to outdoor educator and former ski patrol director Paul Baugher, 90 people died at U.S. resorts due to tree well-induced snow immersion suffocation (SIS) between 2001 and 2025.
Tree wells form in the space around the trunk of a tree, underneath its branches. Because this area is shielded by the tree’s canopy, it sees far less snowfall accumulation than surrounding locations, creating a low-density pocket of snow incapable of supporting the weight of those unlucky enough to fall into it. Those who catch an edge or clip a branch and end up headfirst in a tree well are often unable to escape the quicksand-like conditions, leading to dozens of SIS deaths over the years.
So, how does one avoid a tree well-related death? First and foremost, it is important to always ski with a partner in densely gladed terrain, as those not already in a tree well will be much better positioned to get you out of one. However, sightlines are often limited in the forest, and it is far too easy to lose visual contact with your ski buddy. As reported by Wilderness Medicine Magazine, 72% of those who died in SIS incidents were, in fact, skiing with a partner at the time. It is clear that more safety measures must be introduced to prevent deaths of this kind, and thankfully, OSU-Cascades students may have a revolutionary solution: The Tree Well Guardian.
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Bend, Oregon-based college students Makani Hiltner and Hunter Erhard invented the Tree Well Guardian in response to SIS-related deaths at nearby Mount Bachelor. The device, which started as a class project, is about the size of an avalanche beacon and clips onto the top of a ski boot. When flipped upside down — as it would be if attached to a rider immersed in a tree well — the Guardian sends a precise GPS alert to nearby emergency services. To prevent false alarms, such as one caused by a user taking a tumble on an open slope, the product comes equipped with two 10-second warning periods, during which non-immersed riders can manually shut off the alarm.
While still a prototype at this stage, the project is off to a promising start, having won second place at the 2026 InventOR finals. Given continued progress, it is not difficult to envision a future where the Tree Well Guardian is as ubiquitous as modern safety devices like the avalanche beacon. If and when Erhard and Hiltner’s project becomes publicly available, it could prove revolutionary for the safety of those skiing and riding in forested terrain — perhaps making SIS deaths, at least at their current scale, a thing of the past.
