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Show CHAPTER 6. AVALANCHE PROTECTIVE MEASURES There are three methods by which an area can be protected from avalanches: restrictions, stabilization and barriers. How they are employed depends upon the type and concentration of use and the capabilities of the protective organization. Restrictions Closure of all or parts of an area is the simplest protective measure that can be applied. It is also the least desirable. To some extent it defeats the purpose of developing and using an alpine area. It is at best a passive method of protection which does nothing to reduce the hazard or bring it to a definite end. The advantages of restrictions are flexibility and speed. A hazardous area can be closed in a matter of minutes by announcement, posting signs or closing gates. The goal of any snow safety organization is to employ restrictions as sparingly and lift them as rapidly as possible. Stabilization The methods employed depend upon the circumstances but in any case, all have a common principle] Stabilization of the snowpack. In a winter sports area, the skiers themselves prevent the build- up of dangerous avalanche conditions by constant use of the slopes. They promote rapid settlement and consolidation of each new snowfall, the shearing action of skis cuts all tensions and guarantees that no slab layer will be buried in the snowpack to make trouble later on. Stabilization by constant use is the reason that a slope, a notorious slidepath in its natural state, can become a favorite ski run of almost non- existent hazard. Practically all the great alpine ski areas have this same history. Stabilization by use is highly effective but requires planning and supervision. If observations indicate the likelihood of hazard, the process begins with test skiing. This is always done by professionals, at least two working together. One, using the avalanche cord, skis the release points of the slopes. The other keeps watch and belays his partner on a safety rope if they are working on cornices or high- angle slidepaths. Test skiing becomes protective skiing if actual avalanches are released. If this operation is carried out by properly trained men, with due regard for the character of the slidepath and the snow, adequate safety can be maintained. But it is definitely not a game for the amateur. Ordinarily, test and protective skiing are confined to areas where continuous use assures that the snowpack as a whole is stable and only the surface layer can avalanche. - 62 - |