A breathing device which extracts air from snow could help avert avalanche tragedies such as the one that killed four climbers in Scotland just after Christmas.
The AvaLung, invented by an American professor from Denver, Colorado, can keep a person buried in snow alive for up to an hour. Normally, the chances of surviving burial in an avalanche are slim.
About a third of victims are killed when they are hit by rocks, trees, debris or simply by the force of the snow itself. For the rest, survival is possible only if they are found and dug out quickly. But after 35 minutes suffocation will have killed 70% of those buried alive.
The AvaLung gives victims extra time. It works by exploiting the fact that even avalanche debris contains 40% to 60% air, and that light, powdery snow can have an air content as high as 90%.
The problem is that the mouth and nose do not provide a large enough surface area to extract the air from the snow.
Professor Thomas Crowley, from Colorado University, hit on the idea of a device attached to a victim's clothing which could squeeze air from the snow.
New Scientist reported yesterday: ''He conceived a device in which a broad, hollow chamber, covered by a filter, is sewn into the front of a jacket and attached to a breathing tube. To keep carbon dioxide levels down, valves direct exhaled air to a chamber on the victim's back, where it is vented.''
Last year the device was tested on three volunteers who elected to be buried in snow on Mount Hood, Oregon. Oxygen levels for two of the three remained above 90% of saturation after an hour. For the third the oxygen level fell to 81% after 45 minutes.
But experts cautioned that the AvaLung was no substitute for shovels, beacons, and training.
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