18/12/2025
Myth: Busted ❌
Historically, 2 out of 3 critically buried avalanche victims asphyxiate within 35 minutes. Over the years, many theories have tried to explain why breathable air disappears so quickly under the snow.
One of the most persistent?
The formation of a solid “ice mask.”
The idea is that warm breath melts surrounding snow, which then refreezes into an airtight layer, blocking gas exchange.
While ice lenses have been documented in real accident reports, they’re most commonly found after long-term burials — several hours or even days later — when professional rescuers recover victims.
When it comes to the short asphyxia window, we've always found this to be an unlikely cause of asphyxia under the snow. Based on our years of research, we’ve long hypothesized that:
1️⃣ Snow remains porous during the initial asphyxia window, even with warmed exhaled air
2️⃣ Avalanche-density snow does not need to become solid to trap dangerous levels of exhaled air in that time frame
’s clinical trial of SBX put this to the test.
24 volunteers were buried — half using Safeback SBX, half with placebo devices. During each trial, four sets of sensors were placed around participants to track gas movement (or the lack of it) through the snowpack.
Their study confirmed that:
1️⃣ Snow remains air permeable for the full historic asphyxia window, demonstrated by SBX's continuous effect throughout the entire test period
2️⃣ Avalanche-density snow is capable of trapping exhaled gases when buried without a Safeack device, where recirculation in the body eventually leads to low Oxygen and high CO2 levels in the air they have access to breathe.
Read the study via the link in our bio - you'll find all of the data on gas saturations presented in the supplemental information attached to the study.
