|
pointed stick, such as a ski pole with the basket removed, with a reversed ski pole, or with the heel of a ski. Although this does not permit visual examination, it will indicate any hard crust or probable wind slab below the surface within a depth corresponding to the length of the pole. The skier must remember, however, that ski-pole detection will not go far enough to disclose the most dangerous avalanche hazard—that of several feet of surface snow avalanching on a deeply buried but poorly bonded underlayer. Frequently it is desirable to know the probable condition of snow at so distant a point that it cannot be directly examined. This, and the condition of underlying snow which cannot be readily examined, is best learned by study of past weather conditions. Records of weather must be used with caution, as local variations due to slope exposure, wind, and altitude, may make notable difference. Weather reports may serve, however, to a limited extent. For example, if temperatures well below freezing are reported to have prevailed prior to and during a snowfall, there will be a greater danger of avalanche following the snowfall than if the temperature is known to have been above freezing prior to and during the first stages of the snowfall, followed by lower temperatures during the balance of the storm. Or, if rain or a heavy thaw were followed by a freeze and then by additional snowfall, an impermeable ice crust would probably have formed, which would provide poor bondage for overlying new snow, and over which water from the thawing snow might collect as a lubricant for a subsequent avalanche. |
|||
|
