Avalanches are grave danger for skiers, climbers, military personnel and others in mountain regions during winter or spring. Death or serious injury can result when a person is buried in snow unless rescue is quickly effected.
Rescue is difficult because a person cannot easily be located. Suffocation, hypothermia, and cardiac arrest, coupled with shock are become a reason of death under an avalanche.
One of the many inventions in rescue field is method and device (US20130335257A1, priority from 2011, by Forsvarets Forskningsanstalt) based on microwave radar (like a previos invention) for searching through collapsed ground and, I guess, through collapsed snow.
The amount of time spent in locating a victim is an important factor in the probability that the victim will not survive or will be severely injured.
For solve this problem, electronic locating systems are being used. Usually, each member of a group exposed to avalanche danger. And each member is supplied with radio transceiver unit operating continuously in a transmitting mode. If part of the group is buried in an avalanche, the remaining members switch their units to a receiving mode and attempt to locate buried victims by variations in received signal strength.
Using surviving forces for locating victims allows execute search and rescue without waiting for the arrival of rescue services. In order to find a buried victim, it is necessary to move about, preferably in a grid pattern, while radio bearing of victim’s transmitter. This can be difficult and time consuming, particularly in the unfavorable terrain common to avalanche sites. The difficulty is compounded by the fact that survivors are often confused or in shock. In addition, if multiple victims are buried, the region of maximum signal strength may not coincide with the location of a victim.
One of usefull inventions is detector and method (EP2573583A1, priority from 2011, by Ortovox Sportartikel GmbH) which shown in pictures below.
And example of apperance is shown in the next (US20060035622A1, priority from 2004, by Ortovox Sportartikel GmbH):
Radio Frequency 457 kHz of the transceiver is generally standard in the rescue industry.This frequency has some advantages (penetration through the snow) and disadvantages (distortions).
There are a lot of players at the market of the same rescue devices. It’s possible to review their products in next posts.