Glaciological research on the ice cap to the north of Lake Hazen in northern Ellesmere Island was one of the main objectives of the Canadian I.G.Y. expedition to this area in 1957–1958. The method of nourishment of this ice cap and of Gilman Glacier, one of its southward-flowing outlets, was studied in pit and bore hole profiles above and below the equilibrium line, which was found at an elevation of about 1,200 m. Between an elevation of about 1,450 and 2,000 m. accumulation is by firn formation, while between about 1,280 and 1,450 m. interfingering of firn and superimposed ice occurs. At 1,800 m. the mean annual accumulation over the past twenty years is estimated as 12.8 g. cm.–2. On Gilman Glacier below the equilibrium line variations in density and crystal structure in an ice core to a depth of 25 m. are seen to depend on the proportion of firn to superimposed ice formed during accumulation. These variations correspond to past changes in the position of the equilibrium line. Englacial temperature measurements indicate a mean annual temperature of about –18.5° C. at an elevation of 1 ,040 m. A budget deficit for Gilman Glacier during two years of observations may be related to the increased summer melting of the last 20 years, deduced from pit studies at 1,800 m.

During the monsoon of 1956 the Geological Survey of India sponsored an expedition to the Bara Shigri Glacier (lat. 32° 16′N., long. 77° 40′E), Kangra District, in the great Himalayan ranges of the Punjab, as part of the Indian programme for the International Geophysical Year 1956–57. Topographical maps of the terminal 3 miles of the glacier, on scales of 1:63.360 and 1:10,000, were prepared for comparison of morphological changes since it was last surveyed 50 years ago. The glacier appears to have shrunk considerably but its full extent could not be assessed because of insufficient earlier data. The Shigri Stream now emerges from a different part of the glacier snout. In order to assist future surveys three photographic stations were established.

Analyses for pH, Na+, K+, Ca2+, Mg2+, HCO3−, Cl−, SO42− and NO3− have been made on land ice samples from Nordaustlandet, Svalbard. Total ions range from less than 0.02 to 0.46 milli-equivalents per litre, with sea salt generally the dominant component although calcium and magnesium bicarbonates are relatively more abundant in a surface sample heavily contaminated by soil material from an adjacent moraine. These ions, as well as potassium and sulphate, are present in most samples in excess of possible sea-spray supply. From the surface of a crevasse to 14 m. depth down one side the concentrations of all ions except nitrate fluctuate in a similar manner. Some possible implications of the results are examined.

The glaciological work of the Australian National Antarctic Research Expedition in 1957–58 is described, and some results are given in general terms.

Weekly observations were made on the horizontal and vertical components of surface movement of the Sefstrøms Gletscher, north-east Greenland. It is concluded that in the area in question the state of the glacier is consistent with Nye’s concept of extending flow. Melting observations were also made. An estimate of ice thickness, derived from measurements of surface slope, is given.

A group of previously unmapped glaciers on the slopes of Trident and Katmai Volcanoes, southwestern Alaska, was studied for information on the abnormal regimen produced by effects of the 1912 eruption of Mount Katmai. During the eruption an area of 5 square miles (13 km.2) of the summit above regional snow line was destroyed, and the beheaded glaciers were buried under a blanket of pumice and ash. Field data are presented to indicate that the terminus of Fourth Glacier has been essentially stationary since the 1912 eruption. Upper portions of the glacier have thinned, exposing the rim of the caldera which 40 years ago was partly ringed with fringing ice cliffs. Permafrost has developed to within a few feet of the surface of the pumice mantle. Under prevailing climatic conditions Fourth Glacier may be preserved in its present static condition for an indefinite period.

The distribution of velocity along a vertical line in Greenland is calculated. Almost all the relative shear motion is concentrated at and very near to the bottom, and this result is thought to apply generally in Greenland and Antarctica. It is due to the relatively high temperature of the lowest layers and the strong dependence of creep rate on temperature. The outward velocity being thus almost constant with depth, it is assumed proportional to the mth power of the shear stress on the bed; the results previously obtained by the approximation of perfect plasticity then correspond to m→∞. Steady-state solutions for finite m are derived, and non-steady states are discussed by use of Weertman’s perturbation method. The steady-state height of an ice sheet is found to be very insensitive to the rate of accumulation. Surface waves in Antarctica are attributed to mountains buried beneath the ice, and it is shown how the height and form of a buried mountain ridge may be calculated from the associated surface disturbance.

The application of a law of sliding to glaciers leads to an expression for the longitudinal strain-rate, hitherto an undetermined parameter.

This paper is a synopsis of Falkland Islands Dependencies Survey Scientific Report No. 29. Glaciological and climatic investigations carried out in South Georgia during the International Geophysical Year are described. The budgets of the Hodges and Hamberg Glaciers for 1957–58 are given and discussed in relation to climatic factors. Temperature measurements indicate that the Hodges Glacier, and probably all ice in South Georgia below an altitude of 1,000 m., is geophysically temperate. The fluctuations of South Georgian glaciers during relatively recent times are briefly discussed.

The Yakataga Glacier occupies a steep-walled valley in the Robinson Mountains on the north coast of the Gulf of Alaska. The main trunk of the glacier descends from 1130 to 150 m. in a distance of 21 km. A rock fall at the head of the glacier formed a moraine of distinctive shape which advanced at an average rate of 114 m./yr. from 1938 to 1954. The surface velocity of the glacier at fifteen stations below the firn line was calculated from the displacement of the rock-fall moraine and other less conspicuous features that are shown in two sets of vertical aerial photographs, taken in 1948 and 1954. For this time interval the average surface velocity along the medial line of the glacier ranged from a maximum of about 90 m./yr. at a station 14 km. above the terminus to zero at a station 2.3 km. above the terminus. The technique of photogrammetric measurement of surface velocity by using natural features on the surface of a glacier has wide application in Alaska, where many glaciers have been rephotographed from the air after intervals of a few years to as many as thirty years.

Twelve deep pits (5 to 5.5 m.) revealed between 6 and 13 years of snow accumulation. The results show an average net accumulation of 18.5 g./cm.2 per year. Accumulation decreases inland at a mean rate of 1.5 g./cm.2 per 100 m. rise in elevation. Temperature measurements at 100 m. in all pits give a mean temperature-altitude gradient of 0.77° C. per 100 m. Evidence of melt was observed in all pits, the most pronounced melt occurring in 1954. The mean density reflects the local climate. Other empirical correlations of these data show linear trends that vary systematically with surface slope and local climate.

The expedition to Mauna Loa in Hawaii was undertaken in the winter of 1956–57 in order to study the nature of snow crystals in the district where the fewest aerosol particles are present. 170 photomicrographs of snow crystals were taken at the summit—13,450 ft. (4000 m.). The varieties of snow crystals were abundant and almost all types hitherto known were observed. The characteristic of the snowfall was the abrupt transition of one type to the other. Many single needles were observed, which were very rare in Hokkaido. Two new types were found; one was a needle composed of many hexagonal columns, and the other an elongated column which is the intermediate state of needle and column. Several photographs were obtained which show the mechanism of formation of ice pellets.

Glaciers in fjords almost always reach standstill positions at the fjord mouths or at changes in their width. Between such positions the terminus is usually advancing or retreating: the advance may be anomalous compared to glaciers on dry land in the vicinity, and the retreat may be catastrophically rapid. These peculiarities of fjord glaciers can be at least partly explained by considering conditions to be expected in an ideal fjord of constant width: the glacier cannot reach equilibrium by changing the extent of its ablation area or its calving terminus, and these cannot change their altitude with respect to sea-level in response to a rise or fall in the firn limit.

A ridge of drift emerging from the snout of Flatisen resembles a small esker. It originates in a subglacial tunnel. The source of the material forming the ridge was a number of thrust planes exposed in the sides and roof of the tunnel. The main features of the tunnel and the ridge are described and the mode of formation of the ridge suggested.

A new method for measuring ice tunnel deformation and closure is described. It includes cutting slots into a smooth vertical wall, forcing wet dyed string into the slots and freezing it in. Results of one year’s installation are given for each of 13 grids installed throughout a 366 m. ice tunnel. Two important visual observations are reported. The first is that no differential shearing was found; and the second, that heavy dirt bands that occurred throughout the tunnel appeared to have extruded into the tunnel opening. A possible explanation is that dirty ice is more plastic than clear ice.

As a result of an historical sketch of scientific activity on Mount Washington, New Hampshire, it is shown that the late-season snow-bed that annually forms in Tuckerman Ravine disappeared, on the average, during the first week in August for the period 1922–58 as compared with an average date of 11 August for the period 1878–1906. This appears to correspond to a rise in spring (April to May) and summer (June to September) mean temperatures of 0.9° F. (0.5° C.) for each season from 1872–87 to 1933–58. The snow-bed probably has persisted through only one ablation season during recent years, that of 1926, although some evidence exists that it may have lasted through an occasional summer during the early and middle nineteenth century.

Based on an observed temperature profile through the Ross Ice Shelf at Little America and partial profiles in the Maudheim Is-shelf and the Filchner Ice Shelf near the Ellsworth I.G.Y. station, various models of heating with and without melting from below are analysed to find the residence time of the respective ice shelves over the ocean. Estimated movements are compared with observed shelf movements seaward. 100 and 200 yr. melting rates for an ice shelf initially 20.5° C. below the freezing point of seawater are found as functions of the deviation of sea-water from its freezing point and the eddy conductivity of the ocean below the ice shelf. Steady-state solutions based on constant accumulation and sinking in an ice shelf of constant thickness are discussed.

The effect of heating of an ice shelf from above and below as it moves to a warmer atmospheric environment is described and it is concluded that the decreasing temperature with depth found only in the Ellsworth ice is a result of its rapid motion from the cold region to the south-east of the station (Coats Land).