Snow Avalanche Hazards and Mitigation in the United States (1990) / Chapter Skim
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5. Avalanche Control
5. Avalanche Control
Pages 37-46
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From page 37... ...
active methods, which involve systematic attempts to artificially trigger small nondestructive avalanches as a means of reducing the hazard as well as to test the accuracy of avalanche hazard forecasts, and (2) passive methods, which include anchoring or modifying the snow in avalanche starting zones so as to eliminate the release of large destructive avalanches and the construction of various structures to divert or dissipate the force of an avalanche in track or runout zones.
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From page 38... ...
ski areas, requires avalanche control technicians to ski or walk to predesignated delivery sites and physically throw charges into known avalanche starting zones. Costs are comparatively low when a large number of avalanche Oaths are concentrated in easily accessible areas and the placement of explosives can be .
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From page 39... ...
Of Austrian and German origin, over 120 cable explosive transport systems are now used in France alone for ski areas and transportation routes (Brugnot, 1987, 1989; Borrel, 1987; Rapin, 1989~. Using manual or powerec} drives, cable delivery systems transport explosive charges to avalanche starting zones on a cable tramway.
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From page 40... ...
The recoilless rifles are lighter than the howitzers, and because of their low recoil they allow lighter support structures and permanent gun emplacements. Permanent gun emplacements in turn permit instrumental alignment for blind firing during periods of poor visibility.
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From page 41... ...
Army would supply surplus weapons and ammunition, with repair and training support, to local USFS offices. The USFS would administer the program and assume responsibility for training gun crews, operating the program, and maintaining public safety.
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From page 42... ...
~. Also, recoilless rifles yield a substantially increased dud percentage when used at over half the maximum range (Peria, 197Sb)
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From page 43... ...
Nevertheless, machine compaction is not widely used, chiefly because of the inaccessibility of many starting zones and the current high costs of vehicles and cable belay systems. STRUCTURAL CONTROL OF AVAI^NCHES Structural avalanche control includes the natural or artificial anchoring of the snowpack in starting zones, structure-influenced redistribution of the snowpack in starting zones, and the structural protection of lives and property located in known or suspected avalanche paths.
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From page 44... ...
Installation and maintenance may be expensive. Other redistribution structures include snow fences, which are usually located on flat ridge crests above starting zones or on windward ridges (Norem, 19784.
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From page 45... ...
The hazard of access into or out of reinforced structures remains unchanged unless diversion devices are also installed. New structures built in avalanche paths in the United States may have reinforcing features designed into their construction.
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From page 46... ...
development of certification standards based on both written tests and weapons handling ability; e. training in procedures for weapons maintenance and ammunition storage and transportation; and £ training in the documentation, location, and disposal of duds.
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