Observations were made at 19 sites in and around the Fort Greely Military Reservation in Alaska during the winter of 1966-67 to obtain data on the depth and physical properties of the snow cover. Snowfall in 1966-67 totaled 245 cm, which was more than 2-1/2 times the seasonal normal. Maximum snow depths of 80 to 100 cm were observed in a major portion of the reservation. Measurements at nine sites showed that the snow density at Fort Greely was generally light; e.g., the average density in the forest did not exceed 0.24 g/cu cm. However, exceptions such as at Jarvis Creek, where the density averaged 0.33 g/cu cm, could be expected. On the average, less snow falls at Fort Greely than at other interior Alaskan locations; but the average density of the snow cover at all interior Alaska sites is quite light. Relationships between snow-cover properties and climate were tested using data collected at Fort Greely. The results substantiated the relationships between (1) snow hardness and snow density measurements and (2) average snow densities with average windspeed and air temperatures. Snow temperature measurements at Fort Greely showed that the snow in the forest was colder than at exposed sites, primarily because the average air temperature within the forest canopy was lower than that in the open area. (Author).

The Fort Greely area in the interior of Alaska is especially interesting because it has such a wide variety of snow types. It contains the low density snow, consisting mostly of depth hoar, which is typical of wind sheltered valleys. It also has hard windpacked snow in unforested places because of the prevalence of strong winds from Isabell Pass in the Alaska Range. The snow structure evolves through the winter in different ways, depending on exposure to wind and to temperature gradients in the snow. The effect of snow structure on vehicle traffic is extremely variable from place to place. This is documented by measurements of density, temperature, and ram hardness together with 21 photographs and 9 line drawings.

The physical, meteorological and climatological aspects of freezing precipitation in the Tanana River Basin of central Alaska are examined. Periods of inclement weather are evaluated with respect to frequency and duration, and concurrent temperature, wind, atmospheric pressure and visibility conditions. Although relatively dry polar continental air masses dominate the area in winter, massive intrusions of maritime air occasionally produce a major snowstorm and, in rare instances, rain or freezing rain. Because of the surrounding mountain ranges, snow occurs most often when the atmospheric pressure is rising and the winds are from the west. Ice fogs are observed at temperatures below -21F, and very few water-droplet fogs are reported at temperatures below -31F. The relationships between air masses, fronts and local climatic influences may be used in forecasting winter precipitation in central Alaska. The statistical survey presented also contributes new information on winter weather conditions in this region. (Author).