Item: The AK Block, A Sized Non-cutback Snow Test
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Title: The AK Block, A Sized Non-cutback Snow Test
Proceedings: International Snow Science Workshop 2014 Proceedings, Banff, Canada
Authors:
- Bill Glude [ Alaska Avalanche Specialists, Juneau, AK, USA ]
- Randall Mullen [ Crazy Mountain Research, Bozeman, MT, USA ]
Date: 2014-09-29
Abstract: The AK Block is a large block snow test sized to the tester's weight and their ski or snowboard contact length, dug out on three sides, and loaded by a person on skis or snowboard. It was developed to maximize the large block advantages of simulating human triggering, identifying the most-critical weaknesses, error tolerance, propagation testing, numerical score plus direct sensory feedback, and minimizing the effects of spatial variability. The AK Block takes less time than other large blocks, and avoids, the back cut that is difficult to do properly. It accounts for tester weight, and tests the slab and weak layer as an integrated system. The AK Block is simple to set up, using the skis or snowboard to provide crack initiation. Earlier analysis of 357 blocks over 120 field days indicated that the AK Block is a valid predictor of avalanche days. This new statistical analysis follows the methodology used in evaluating the Extended Column Test and Propagation Saw Test, allowing better comparison of the AK Block with other tests. Results suggest that the AK Block is more accurate at detecting unstable days than the Rutschblock, and has a lower rate of false stable results. Its predictive performance is comparable to that of the Propagation Saw Test, but less accurate, and with a higher false stable rate, than the Extended Column Test.
Object ID: ISSW14_paper_P2.28.pdf
Language of Article: English
Presenter(s):
Keywords: avalanche, snow stability tests, block tests, sized-block, AK Block, Rutschblock
Page Number(s): 799-805
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