The techniques of avalanche forecasting and control have found increasingly wide adoption in North America in the past decade. Numerous government and private agencies are now engaged in work to protect ski areas, highways, railroads and power lines. Practical control measures such as artillery fire have been developed to a high degree of effectiveness, but the construction of permanent defense structures other than snow sheds is still in its infancy. Experimental work on instrumentation, forecasting, defense structures and the use of explosives, artillery and jet aircraft is currently in progress.

The lemniscate loop, previously employed in the approximate generic description of the shapes of erosional drainage basins, is shown to bear a close genetic relationship to streamlined forms. This is illustrated by comparison with the shape of airfoils, the snowdrift and certain eggs. Drumlins have been recognized as similar streamlined forms and the lemniscate loop is suggested as providing a quantitative genetic description of their shapes.

Both long and short-term snow ablation measurements usually contain errors when made with a simple ablation stake. Ablations measured over long periods for glacier regimen studies are subject to a settlement error in even dense snow, corrections for which may be made by simultaneous measurements with stakes of different lengths. For observation periods in the order of twenty-four hours or less, both mass loss and ice melt are often poorly represented by the simple product of mean bulk density and change in surface level. These quantities may be measured directly by successive determinations of bulk density and ice density profiles in the surface snow layer. Under certain favorable conditions, they may also be derived by observing directly the total and ice mass changes in a sampled area of the snow surface.

The evidence for the existence of small glaciers in the cwms of the Caernarvonshire mountains during the Late-glacial Period is presented, and by an analysis of their distribution some of the factors responsible for their formation are deduced. These were primarily protection from insolation, drifting of snow into the cirques by wind and the distribution of precipitation.

A review of the inadequacies of the glacial moulin hypothesis for the origin of potholes.

In an uncompleted paper, the glaciological observations made by the late Michael Holland and his party in the mountainous Sukkertoppen region of West Greenland (lat. 66° N.) during the summer of 1956 are described. Notes on the features of this region and of the present state of the glaciers were fairly complete; it is felt that these should be put on record as likely to be of use to future workers. It is concluded that in recent years retreat of the main glaciers appears to have been very slight. Pit measurements were made and tabulated and comparisons were made with the earlier findings by Etienne in the same area. No notable difference in the annual accumulation is yet apparent; it is tentatively concluded that there may have been a small increase, but caution is heeded in interpretation as the nearest meteorological stations lie at some distance.

Unusual thrust structures in thin sea ice sheets were observed in Labrador and Greenland. These structures are the result of thin ice sheets being of wind and waves. When thicker pack ice is subjected to these same forces pressure ridges result.

In addition to field observations and quantitative analyses of natural phenomena, an opportunity exists for the application of glaciological knowledge. Major problems preventing the widespread use of ice and snow as structural materials are related to processing methods, properties of ice and snow, and deterioration during the melt season. These difficulties have been considered and an experimental program carried out to determine the feasibility of developing practical methods for using ice and snow as engineering materials. Results show that the development of improved processing methods for both ice and snow, the development of ice alloys with improved properties, and the extension of the use season provide real opportunities for applied glaciology.

An unusual opportunity for the study of glaciers in the process of development is afforded in Katmaicaldera in south-western Alaska. A violent eruption in 1912 destroyed the summit of glacier-clad Mount Katmai, creating a caldera 4 km. wide and 800 m. deep. Ice cliffs produced by beheading of the glaciers have since thinned and shrunk away from the rim of the caldera, except in the south-west. There, local reversal of direction of movement has resulted in an ice fall which descends part way down the crater wall. In the past thirty years two small glaciers have formed, near 1525 m. above sea level, within the caldera on large masses of slumped wall-rock below the north and south rims respectively. Elsewhere the sheer walls of the crater descend so steeply to the level of the caldera lake that permanent snowbanks cannot accumulate. The lake, which continues to rise at a rate of more than five meters per year, is at present the primary deterring factor in glacier development in the caldera.

The compressive strength of snow cylinders was investigated as a function of the age of the snow from which the cylinders were made, the snow particle size and the age of the cylinders. The results show that the compressive strength is reduced if the snow is older, if the particle size is smaller, or if the cylinders are younger. The variation with age of the cylinders can be represented by an equation similar to that for a first-order chemical reaction. The effect of adding small quantities of various gases to the atmosphere in which the cylinders were kept was also investigated; carbon dioxide and methane had no measurable effect, but ammonia lowered the strength of the cylinders. All the strength measurements were carried out at −10° C.

A series of deformation measurements have been selected for preliminary studies on the plasticity of Greenland glacier ice. The measurements to be reported on were obtained in the Red Rock and TUTO tunnels in north-west Greenland. Both tunnels were excavated during the summer of 1955 with some additional work done during the summer of 1956. Deformation measurements made up to the end of the 1956 summer season, therefore, are of limited reliability, but certain trends appearing in these data seem worth reporting. The topics discussed are (1) the shearing of an initially vertical peg system at Red Rock, (2) the deformation of core holes at TUTO, and (3) tunnel closure at both sites. These data are analysed on the basis of laminar flow of the Nye type and certain conclusions are derived.

Contributions to the glaciology of the Himalaya, Karakoram, and Turkestan areas are contained in the hitherto unpublished records of the Schlagintweit brothers. These should be of considerable value for future research since the records include paintings, sketch maps, descriptions, and also measurements of glacier speed, which give details of the state of the glaciers in 1855–56. These records were used recently to great advantage on Nanga Parbat.

Motion produced by ice expansion and by wind-blown ice cakes has modified the shores of lakes in northern New England, U.S.A. Twenty-six lakes have been studied, the processes observed, and measurements made of the rate and extent of ice action. Conclusions as to the effectiveness of the two processes are brought out.

An investigation has been made on the amounts and composition of gases enclosed in West Greenland glaciers ranging from the Thule area near lat. 77° N. to Brede Fjord at lat. 62° N. In general, the gas composition deviated appreciably from that of air, and also varied within each piece of ice. Presumably these variations are caused by melting either in the firn area, or, more often, at the outlet sites. 13C analyses indicate that organic contamination of the snow may be another factor. Undisturbed ancient atmospheric air was therefore not encountered in our Greenland samples, but indications are that it might be found in the much colder Antarctic ice sheet. Gas bubbles analyzed from crack fills in icebergs had high oxygen concentrations, sometimes almost matching that of air-equilibrated ice-cold water, from which they undoubtedly originated. Blue icebergs, which often were seen floating up from the bottom of glacier fronts, also tended toward high oxygen concentration and very likely, therefore, are caused by freezing of melt water seeping down and collecting underneath the glacier.

During the summer of 1955, 53 thermocouples were installed in the ice mass near a crevasse in a glacier in the ice sheet of northern Greenland. Temperatures were observed in 1955 and 1956. The accumulated data were sufficient to prepare a description of the transient thermal behavior of the ice body adjacent to the crevasse. The isotherm maps have provided a base for the computation of heat flux vectors.

The critical density of newly fallen snow was measured during the 1956–57 winter season at two stations: Montreal Road Laboratories of the National Research Council, Ottawa, and the University of New Brunswick, Fredericton, New Brunswick. The relative compacted density or compactibility of newly fallen snow was found to depend on undisturbed density and snow temperature. A statistical equation was developed relating snow temperature and undisturbed density to the compacted density of the snow sample. Additional tests under cold room conditions indicate that grain size and grain-size distribution also have an appreciable effect on compacted density.