OCR Text |
Show of the prevailing cold weather its consistency was light, being either fleecy or granular. It was blown into great drifts in the canyons and overhung the crags and ridges at the summits of the mountain ranges. " On the morning of February 23 a low- pressure area made its appearance off the Washington coast, which was attended by milder weather, high winds and a heavy fall of snow in the mountains. It was three days in passing from the coast to the eastern side of the Rocky Mountains, and during this time the snow accumulated in large quantities at the heads of the canyons. Numerous avalanches occurred during this storm, but they mostly came down in places where the snow slides every year and there was nothing unusual about them. " The storm of February 23 had barely crossed the mountains when another low- pressure area made its appearance on the North Pacific coast, and it was quickly followed by a third disturbance. It took each of these storms two days to move to Alberta and they all followed nearly the same track. " The last two storms caused high winds and also heavy rains that extended well up the slopes of the mountains while at the summits the precipitation was mostly snow which was very moist and heavy. In fact, as a result of these two storms all the recent falls of snow became soaked with moisture and beneath this was the first snow which had almost the consistency of ice, conditions that were ideal for the occurrence of avalanches." This analysis, written over 40 years ago, contains some very acute observations. In fact, one statement in the report could well be adopted as a motto by all avalanche observers: " It was not the quantity of snow . . . that caused so many avalanches, but . . . the manner in which it fell." By study of avalanches, the Forest Service undertook to obtain maximum public use of alpine ski areas with adequate public safety. It was obvious from the start that snow and avalanche research in this country would take a course different from that being carried on in the Alps. We had neither the time, the funds, nor the trained personnel to engage in basic research. Our efforts had to be directed toward the rapid development of field techniques for the recognition of hazard and for the reduction of hazard. This was a difference in scope. There is also a difference in time and space. The Alps are compact. A given set of weather and snow conditions will influence hazard throughout most of the area. The United States is very large with endless variations of weather taking place simultaneously. Our areas in need of avalanche protection are widely separated in space and with marked differences in climate. Our protective service therefore must be localized. - 11 - |