OCR Text |
Show Monthly Weather Summary (Sample - Dec. 19U7) Total snowfall Water content Snow settlement Net gain Avalanche occurrence 80" 67" 9 n (Ug" to 57") Large Medium Insignificant December g December 7 and 9 12 days 0 2 (snow removal 1; snow 0 removal hazard 1.) 3 days 1 (December 6 - 9 ) Highway closed Highway travel restrictedSki area closed Ski area restricted Major storms Use 1 5 , 2 6 5 Except for the storm early in the month, weather conditions were generally mild. Skiing was excellent throughout the month during a period when many important ski areas have been unable to open due to lack of snow. After remaining consistently higher than the average for the past 2 years, the snow depth dropped well below the average in the third week. Avalanche hazard was generally at a low ebb except during the storm mentioned above. From an analytical standpoint this storm was rather interesting, It produced three distinct avalanche cycles: dry snow slides, slab slides, and slab plus dry snow slides. Each cycle and the factors producing it were much more plainly divided from the others than is ordinarily the case. The dry slide cycle occurred on December 6. With moderate snowfall and non-critical winds, it was correctly diagnosed as unimportant. After a break of several hours the storm began again the afternoon of the 6th and snowfall continued through the night v/ith wind force at critical levels. This cycle too was diagnosed as medium in intensity due to the moderate amount of new snow involved, iiinor restrictions on the highway and ski area were lifted as soon as field testing and observation confirmed this judgmont. The cycle was over by noon. However, it was observed that some slide areas had not discharged their unstable snow. After another break, the heaviest snowfall of the storm occurred during the night of the "Jth and morning of the 8th with only moderate wind. The danger was recognized that some of the areas which had retained their slab might now avalanche in dangerous volume under the weight of the new snow. Skiing was restricted to the safe area: Nina Curve to Wildcat. -6g~ |