457kHz personal rescue beacons

http://www.pieps.com/en/avalanche-transceivers/231-pieps-vector

When in Switzerland last week and thumbing through magazines I noticed references to 457kHz personal rescue beacons to help locate people buried in avalanches. They are small, lightweight, like GPS units, and have a range of 40-80m and a battery life from a single cell battery of up to several hundred hours.

There is useful information on these at http://en.wikipedia.org/wiki/Avalanche_transceiver and on http://www.pieps.com/en/safety-equipment/232-pieps-backup .  Although of no direct amateur radio application, I thought this an interesting device.