Item: Passive Avalanche Defense Mounds in the Bull of the Woods Avalanche Path, Wyoming
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Title: Passive Avalanche Defense Mounds in the Bull of the Woods Avalanche Path, Wyoming
Proceedings: International Snow Science Workshop 2016 Proceedings, Breckenridge, CO, USA
Authors:
- Jamie Yount [ Wyoming Department of Transportation, Jackson, WY, USA ]
- Brian Gorsage [ Wyoming Department of Transportation, Jackson, WY, USA ]
- Rod Newcomb [ American Avalanche Institute, Jackson, WY, USA ]
- Lee Elder [ USDA Forrest Service Rocky Mountain Research Station, Fort Collins, CO, USA ]
- Kelly Elder [ USDA Forrest Service Rocky Mountain Research Station, Fort Collins, CO, USA ]
- Galen Richards [ Wyoming Department of Transportation, Jackson, WY, USA ]
Date: 2016-10-02
Abstract: On February 16, 2014 a large natural avalanche (HS-N-R5-D5) released in the Bull of the Woods avalanche path at milepost 156.5 on US 191 in the Hoback River Canyon near Jackson, WY. The dust cloud deposited 15 cm of snow onto the highway and destroyed many trees in excess of 100 years old with the associated air blast. The highway was spared from this large avalanche due to earthen avalanche defense mounds that were built in 1970. The mounds were effective in dissipating the avalanche's energy and arresting the debris before it reached the highway. The winter of 1949 was one of the largest winters on record in the Jackson area. During that winter a class 5 avalanche at the Bull of the Woods crossed the Hoback River and then gained 35 m in elevation to reach the old Highway. It is believed that this event was the catalyst for the avalanche defense mounds being built 20 years later. This type of passive avalanche defense was very progressive during the 1970's era of avalanche mitigation in the United States. The following case study explores the effectiveness of the mounds, the return interval of the event through dendrochronological analysis, and the historical significance of constructing passive avalanche defense for a low avalanche hazard index highway corridor.
Object ID: ISSW16_P1.10.pdf
Language of Article: English
Presenter(s):
Keywords: passive mitigation, defense mounds, berms, dendrochronology
Page Number(s): 548-555
Subjects: avalanche defense mitigation method dendrochronology
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