Gas Mechanics in Snow

In order to start designing our product, we needed to understand and model how gases move through snow.

Avalanche burial victims today have a limited air supply under the snow, meaning that recovery within 15 minutes is vital to reduce the chance of asphyxiation.

Safeback SBX is designed to draw air from the snow surrounding the backpack and deliver it to the burial victim’s breathing area. The air delivered near the face serves two purposes; supply fresh air to the victim, and transport expired air away from their breathing area.

Affecting Gas Composition Under Snow

Snow is a porous medium, meaning that air exhaled by an avalanche victim, and air from our system will travel through the snow. The characteristics of the airflow are determined by the density of the snow, and the pressure applied by the source - be it the victim’s own breathing, or the Safeback SBX.

To ensure that the Safeback SBX clears away the air that has been exhaled by the victim, we collaborated with the product engineers at Eker Design to create theoretical and Computational Fluid Dynamics (CFD) models to estimate how much airflow and pressure are necessary to supply the victim with fresh air, ensuring that the effects of asphyxia are delayed as long as possible.

Key Findings

Based on the air pressure and flow generated by the Safeback SBX, the shoulder outlets should be placed within 25 cm (10 in.) from the face in order to be able to supply enough fresh air to delay asphyxia for the avalanche victim without draining the SBX batteries too quickly. Model demonstrating the estimated area filled by the victim’s breathing, and the direction which Safeback SBX is designed toclear away the expired air.

More Research & Development

Snow Burial Simulations

To confirm the findings of our modeled research, we created burial simulations to test iterations of our system and measure the actual airflow it generated in the snow.

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Medical Needs of Snow Burial Victims

Based on the problem set of oxygen deprivation during avalanche burial, independent medical trials were conducted by the Mountain Medical Research Group at the University of Bergen.

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Technical Solutions for Supplying Air Through Snow

Developing the Safeback SBX system has required significant testing of all components, both individually and as an integrated system.

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Backpacks with Safeback SBX

Safeback SBX

Designed to provide breathable air to an avalanche victim under the snow, extending their potential survival window.

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