These images are from a simulated burial - my own. The real thing isn't nearly so much fun.
Seventy-five percent of avalanche deaths are caused by a lack of oxygen (an airway blocked with snow) and/or CO2 poisoning. Time is of the essence: Buried victims have a 90-plus percent chance of survival if they're dug out in under 15 minutes. After 35 minutes that chance drops to 30 percent.
Without a sizeable air pocket (one or two liters), your chances of surviving a 30-minute burial are small. A Black Diamond AvaLung boosts your odds by routing your toxic CO2 behind you.
Dense maritime snowpacks can be heavy enough to inflict their own trauma in a slide or compress a victim's chest so tightly that it's impossible to inhale.
Twenty-five percent of avalanche deaths are attributable to trauma, often inflicted when a slide drags a skier over rocks and cliff bands and into trees. As you ski, always think about where a slide will take you. There is also some evidence that even mild head injuries can accelerate asphyxiation by impairing consciousness.
CO2 AND ICE MASKS
Rebreathing your exhaled air leads to hypoxia (a lack of oxygen in the blood) and hypercapnia (excessive CO2 in the blood). Over time, the combination leads to death. Even if you're lucky enough to have an air pocket, your warm exhalations will hit the snow and form an ice mask, trapping CO2 and blocking oxygen from reaching you.
If asphyxiation or trauma doesn't kill you, then hypothermia might. Assume any victim is hypothermic. Field-treat accordingly to avoid a post-rescue core-temperature drop.
Click here or on the "Related Articles" link below to see more images from a 2005 hypothermia study.