Posted on 02/04/2005 8:12:33 PM PST by neverdem
HOW IT WORKS
AVALANCHE rescue beacons have become standard equipment for many skiers and snowmobilers who go into wilderness areas or beyond the boundaries of ski resorts. The small radio transmitters, strapped to the body, can aid rescuers in locating someone buried under several feet of snow.
But not everyone who enters the backcountry uses the devices. Shane Maixner, a 27-year-old snowboarder from Sandpoint, Idaho, was not wearing one when he was caught in an avalanche on Jan. 14 in an out-of-bounds area near the Canyons resort in Utah. A team of rescuers found his body two days later.
"With that accident in Utah, avalanche hazard at the time was considerable to high," said Marcus Peterson, general manager of the United States office of Ortovox (www.ortovox.com), a German maker of avalanche beacons and other outdoor gear, in Hopkinton, N.H. "They had no avalanche equipment, and in this particular instance it was deadly."
Mr. Maixner was the seventh person killed by an avalanche in Utah this season. While a beacon may not have saved his life, Mr. Peterson said it would have made the search easier and less risky.
Current beacons are designed to be used by novices, and are available for purchase (at a price of several hundred dollars) or for rent at many ski resorts. But the first avalanche transceivers, developed in the late 1960's, were intended for use by ski patrol members, search-and-rescue volunteers and operators of slope-grooming equipment.
Prof. John Lawton at Cornell Aeronautical Laboratory in Buffalo developed what is usually considered the first practical avalanche beacon, the Skadi, in 1968. It transmitted at a frequency of 2.275 kilohertz. The signal, which was audible, would get louder as the receiver moved closer to the buried beacon. (Beacons use battery power and transmit continuously while being worn; if an avalanche occurs and someone is buried, others in the party set their beacons to receive to search for the victim.)
Beacon technology remained fairly unchanged until dual-frequency models were introduced in Europe in the 1980's. But the biggest developments, the two-antenna transceiver and the first digital model, came in the mid-1990's.
Working with Backcountry Access of Boulder, Colo., John Hereford patented the Tracker DTS (for Digital Transceiving System), a model that shows the direction and distance from the victim. Newer models like this are designed to be compatible with older ones.
"The Tracker is idiot-proof," said Kim Havell, a rescue volunteer for San Miguel County in Colorado. "You can identify and locate beacons a lot faster."
Speed and accuracy are obviously important when searching for an avalanche victim. If the avalanche does not cause fatal injuries, there is only about a 15-minute window to rescue a victim before suffocation occurs. Without a beacon, the only hope is that the victim is visible above the snow.
That was the case for Bruce Edgerly, vice president and co-owner of Backcountry Access (www.bcaccess.com) when he was buried in an avalanche with just a few fingers poking out from the snow. "It definitely increased my interest in this subject area," said Mr. Edgerly, who was wearing a beacon that day but did not have to rely on it because a friend quickly dug him out.
Today Backcountry Access, which designs outdoor equipment, has helped establish 30 training centers around the world. At Beacon Basin at the Breckenridge Ski Resort in Colorado, for example, experts bury about seven beacons daily in at least three feet of snow for anyone to find.
"Every second counts," Mr. Edgerly said. "In the past, beacons were mainly used by professionals, people who were paid to practice, but use of the backcountry by winter recreationalists has boomed in the past 10 years."
He added that about 95 percent of beacon users today are novices.
So while the emphasis is still on common sense - always go out with a partner, always have a shovel and pole probe as well as a beacon, and assess the snow conditions and slope steepness - the design of beacons has shifted to accommodate these users.
Beacons like the Ortovox X1 and Tracker DTS use digital displays to interpret data, and flashing lights have been added to many models to augment the audio. Traditional avalanche rescue involves walking a grid pattern, but the newer beacons can more closely pinpoint the location of the transmitting buried beacon, saving time.
Will Barrett, an avalanche technician at Breckenridge, said that in most rescues, the searchers were looking for someone they knew. "That's something to think about in terms of why they should practice," he said.
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Interesting technology. Thanks for taking the time to post/ping.
You're welcome. I enjoy the cool technology that comes from science, but I guess you noticed that. ;^)
We use a similar method for marking underground splices. We use a round hollow ball with a bit of fluid in it. In the fluid floats a RFID tag. When a radio locator passes near one it reflects back the signal.
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