OCR Text |
Show - 2- These records do not include every day during the winter when precipit-ation fell. Data were used only from those days on which no rain or sleet fell within the same 2k hours that snowfall was recorded. The density values thus represent snowfall proper which fell at temperatures at or below the freezing point. The mean density figures quoted in Table I are computed by dividing the total snowfall for the entire period of record into the total water content of these snowfalls. This mean therefore is weighted according to magnitude of snowfall, the deeper falls contributing more to the average than the shallow ones. The resulta of this data tabulation are not exactly those which might be anticipated from casual consideration. The highest densities, for instance, are found at Alta, an área long famed for its deep, fluffy powder snow. This reflects a fact known to the experienced snow ranger but usually ignored by the average skier: the best deep powder skiing is not found in the light-est snow, but rather in snow with enough " body" to provide good flotation for the running ski. Density is by no means the entire story in skiing quality, however, as illustrated by the fact that Stevens Pass densities differ very little from those at Alta, though the quality of the powder snow skiing there is not as good. The important differences in this case are probably temperature and altitude. It is also unexpected to find the lowest densities at both of the altitude extremes, Berthoud Pass and Girdwood. Low temperatures and relatively light snowfalls at Berthoud Pass would tend to produce lower densities, although this is to some extent negated by wind action. Much higher densities might be expected at sea levei and warmer temperatures, but it must be noted that the Girdwood observation área is located in a sheltered valley where wind action is limited and also at a higher latitude. The values of new snow densities obviously depend on many |