During the period 8–19 May 1963 a preliminary field investigation was conducted in Greenland to determine the feasibility of using a nuclear technique to determine snow and ice density profiles. A standard nuclear soil-moisture depth probe was used with two modes of processing and recording the nuclear pulses. Example data are compared with snow densities obtained by the standard weighing technique. The nuclear method was found to be feasible; however, deficiencies related to poor resolution render the probe unusable for detailed profiling of snow stratigraphy in its present form, but expected progress in nucleonics should enable improved resolution and accuracy to be achieved by improvement of nuclear detectors.

A description of the two glaciers n. Bogbre and s. Bogbre is given. In summer 1965 snow pillars capped with avalanche material were seen. A blister-shaped swelling which appeared on the surface of s. Bogbre and which emitted water when punctured is discussed.

Stereophotogrammetric techniques were used for a study of snow avalanches. The contour lines of the avalanche slope were mapped from stereo-photographs taken before and after the occurrence of the avalanche. The outline of the avalanche front at certain time intervals and the contours of the snow cloud were also plotted. A relative accuracy for the different maps of 0.7 m. on the terrain was established.

The volume of the snow cloud at four different stages of the avalanche was determined from the maps. These volumes were also computed independently from coordinate readings that were made in the stereo models. The standard errors of both methods of volume determination were estimated to be 450 m.3 and 290 m.3 respectively, representing errors of 5 per cent and 3 per cent of the average cloud volume.

The photographs were taken with an accurately determined time interval. Therefore, the velocity of the avalanche front could be determined from the photogrammetric measurements.

Many elongated hollows about 300 m. long, 200 m. wide and 30 m. deep occur on the surface of Torv Gletscher in a region where the flow of the glacier splits in several directions. Their possible origin is discussed.

A new concept of attitude stabilization for thermal probes or coring drills in ice eliminates instability. The center of support is placed above the center of gravity. A lower and an upper hot point produce melt penetration. The ratio of their power levels is the basis for stabilization. This is provided by the automatic control of the heater in the upper hot point.

A new down bore-hole instrument to extract atmospheric gases entrapped in glacier ice was designed, developed and tested in a Greenland ice tunnel. Using this ice and a 7.5 kW. source, about 30 hr. are required to melt the approximately 1 metric ton sample, extract the gases, and to separate and collect with molecular sieves the minimum of 100 cm.3 of CO2 necessary for the 14C measurements made later using special low-level counters. Age results using the down bore-hole CO2 samples agree with results obtained earlier from CO2 samples collected at the same tunnel location using a vacuum-vessel melting technique. A mean value of 5,120±200 yr. b.p. is obtained for the seven samples measured using both collection systems, making this the oldest natural polar glacier ice measured to date.

Brine volume of sea ice is a function of the salinity and temperature of the ice, and it is related to its strength. This paper gives three equations which can be used to compute the brine volume for three temperature ranges from −0.5° to −22.9°C. A less accurate equation covering the total range is also presented.