The existence of an air pocket in conjunction with an open airway is a definite indication that the buried victim was still breathing after the avalanche came to a halt and gives real hope for survival of the victim. The presence or absence of an air pocket is an important factor in determining the treatment (3) of a victim by the emergency physician after extrication.

Based on a study, in which volunteers breathed into artificial air pockets in snow, we can conclude that length of survival depends on the volume of the air pocket, on the snow density and on other, still unknown, individual factors (18).

At first, hypoxia (lack of oxygen) is combined with hypercapnia (increased carbon dioxide) and, after more prolonged burial, a third factor, hypothermia, comes into play; oxygen demand decreases approximately 6% per degree Centigrade. This combination of hypoxia, hypercapnia and hypothermia has been called "Triple H syndrome”.

An "air pocket” any space in front of the mouth and nose, no matter how small, as long as the airway is clear (4). The definition of "no air pocket” only applies when the mouth and nose completely occluded by snow or vomitus.

Air pockets of backcountry skiers, as described in numerous accident reports, are generally only a few centimeters across. The question "Is there an air pocket or not?" can, in practice, be answered only by careful observation during extrication. By careful extrication and attention, air pockets can usually be identified, because the inner surface is usually glazed.

Due to the significance of this evidence, it is extremely important that it be preserved during the extrication. This should not be rushed. Mountain rescuers and avalanche dog handlers must be made aware of this and trained accordingly, more so than in the past.

In catastrophic avalanches, buried victims can survive for a very long time in large interior spaces of buildings and vehicles. If there is an "open air pocket” which communicates with the outside world and if the upper body is unrestricted enough to breathe, a victim can also survive for hours without cooling to a critically low core temperature.