W
WARY
Well-known member
We just got back to our labs in Minnesota and California from testing an avalanche flotation device (AFD from here on out….) in the mountains of British Columbia. We tested in the Purcell Mountains just east of Invermere, near the Paradise Mine next to Sultana Peak, and in the Brewer Creek Basin.
The results were very promising. A single 170 pound crash test dummy harnessed to a 100 liter (3 cubic foot) lift bag was brought to the surface of 6 consecutive class 2 avalanches. The dummy was found with its head between 15 to 23 centimeters (6 to 9 inches) beneath the surface of the stopped avalanche, usually with the right hand and forearm completely exposed above the surface of the snow. The bright red lift bag was always completely exposed above the snow after the slide, and visible on the mountainside from at least a half mile in good weather. On one memorable class 2.5 avalanche the test dummy and lift bag traveled well over a thousand linear feet down the mountain and then skidded out of the avalanche at the bottom, coming to rest looking uphill at the avalanche as if sitting in a comfy chair at home watching the television. In that case both the test dummy and lift bag were left sitting completely exposed on the surface of the stopped avalanche. Also important, if was common to see the lift bag inside the moving avalanche as it swept down the mountain (sometimes we could see the lift bag throughout the entire avalanche), making searching for the test dummies easier and faster due to the visual aspect of the avalanche flotation phenomenon.
The failures were also sometimes spectacular. In the first case an avalanche that ran big took two crash test dummies over several rock ledges, shredding the lift bags and burying the dummies. One crash dummy (Eve) was lost (CARDA dog search negative) resulting in the remaining tests being conducted with only one crash dummy. The second and final failure occurred when after 6 consecutive successful AFD tests our dummy Adam ran into five 2 meter (6 foot) pine trees at the very bottom of the avalanche, dropped over a small ledge and was buried by the last moving snow of the slide. After half a second the still inflated lift bag popped up out of the snow and settled on the debris field. We found Adam a meter down. We believe the trees started a tear on the already stressed out harness/lift bag interface, and the pressure of the piling snow forced the lift bag free of the harness.
This year we tested an AFD design that is a thin vest worn under your backpack with the rip-cord on your left shoulder and the lift bag deploying over the top of your backpack. Last year we tested (the AFD being tested by 20 volunteers from the www.tetongravityresearch.com forums) a waist belt design that people found difficult to deal with in conjunction with their backpacks. The waist belt design may be more appropriate for in-bounds use for skiers only, and not while riding.
There are now 15 vest AFD prototypes (we call it the Avi Vest) being used by the snowmobile guides at Toby Creek Adventures and we hope to build 250 or more Avi Vests for this coming Fall of 2008.
Our plan for next years testing is to have 2 crash test dummies wearing Avi Vests placed on the mountainside next to 2 snowmobiles harnessed to large AFDs (we successfully floated a snowmobile to the surface of an avalanche in the Ruby Mountains of Nevada several years ago using an AFD. Those tests pics were posted here). One of the test dummies may be wearing skis. There is also the possibility of another snowmachine test later this month in Nevada.
WARI Avalanche Research is a group of engineers, avalanche forecasters, mountain guides and scientists located in labs in Olympic Valley, California (Squaw Valley) and Lakeville, Minnesota (flyover land). We develop rescue devices for people caught in avalanches, rivers, and frozen lakes. We used to post here for years under JTWASSOC.
Thanks to Chris Hrabb at Selkirk Mountain Helicopters for another great year of bombing avalanches and long-lining crash dummies, and a special thanks to everyone who works with Scott Barsby at Toby Creek Adventures, your work on the AFD testing is greatly appreciated.
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The results were very promising. A single 170 pound crash test dummy harnessed to a 100 liter (3 cubic foot) lift bag was brought to the surface of 6 consecutive class 2 avalanches. The dummy was found with its head between 15 to 23 centimeters (6 to 9 inches) beneath the surface of the stopped avalanche, usually with the right hand and forearm completely exposed above the surface of the snow. The bright red lift bag was always completely exposed above the snow after the slide, and visible on the mountainside from at least a half mile in good weather. On one memorable class 2.5 avalanche the test dummy and lift bag traveled well over a thousand linear feet down the mountain and then skidded out of the avalanche at the bottom, coming to rest looking uphill at the avalanche as if sitting in a comfy chair at home watching the television. In that case both the test dummy and lift bag were left sitting completely exposed on the surface of the stopped avalanche. Also important, if was common to see the lift bag inside the moving avalanche as it swept down the mountain (sometimes we could see the lift bag throughout the entire avalanche), making searching for the test dummies easier and faster due to the visual aspect of the avalanche flotation phenomenon.
The failures were also sometimes spectacular. In the first case an avalanche that ran big took two crash test dummies over several rock ledges, shredding the lift bags and burying the dummies. One crash dummy (Eve) was lost (CARDA dog search negative) resulting in the remaining tests being conducted with only one crash dummy. The second and final failure occurred when after 6 consecutive successful AFD tests our dummy Adam ran into five 2 meter (6 foot) pine trees at the very bottom of the avalanche, dropped over a small ledge and was buried by the last moving snow of the slide. After half a second the still inflated lift bag popped up out of the snow and settled on the debris field. We found Adam a meter down. We believe the trees started a tear on the already stressed out harness/lift bag interface, and the pressure of the piling snow forced the lift bag free of the harness.
This year we tested an AFD design that is a thin vest worn under your backpack with the rip-cord on your left shoulder and the lift bag deploying over the top of your backpack. Last year we tested (the AFD being tested by 20 volunteers from the www.tetongravityresearch.com forums) a waist belt design that people found difficult to deal with in conjunction with their backpacks. The waist belt design may be more appropriate for in-bounds use for skiers only, and not while riding.
There are now 15 vest AFD prototypes (we call it the Avi Vest) being used by the snowmobile guides at Toby Creek Adventures and we hope to build 250 or more Avi Vests for this coming Fall of 2008.
Our plan for next years testing is to have 2 crash test dummies wearing Avi Vests placed on the mountainside next to 2 snowmobiles harnessed to large AFDs (we successfully floated a snowmobile to the surface of an avalanche in the Ruby Mountains of Nevada several years ago using an AFD. Those tests pics were posted here). One of the test dummies may be wearing skis. There is also the possibility of another snowmachine test later this month in Nevada.
WARI Avalanche Research is a group of engineers, avalanche forecasters, mountain guides and scientists located in labs in Olympic Valley, California (Squaw Valley) and Lakeville, Minnesota (flyover land). We develop rescue devices for people caught in avalanches, rivers, and frozen lakes. We used to post here for years under JTWASSOC.
Thanks to Chris Hrabb at Selkirk Mountain Helicopters for another great year of bombing avalanches and long-lining crash dummies, and a special thanks to everyone who works with Scott Barsby at Toby Creek Adventures, your work on the AFD testing is greatly appreciated.
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