Detailed account of the work to be undertaken by the International Glaciological Expedition to Greenland during 1959, together with brief notes on the previous researches which have led up to this work.

Wavy perturbations formed on disc-shaped internal melting figures in ice were observed. It was found that a minimum wavelength of the perturbations was approximately 100 μm and a critical thickness of the figures for the formation of the perturbations was 10 μ.m. The critical thickness did not depend on the radius and growth rate of the figures. A minimum wave number of the perturbation was 6 and the axis of its sixfold symmetry was parallel to the <1120> direction, The perturbations with large wave number were formed on the inclined side faces of internal melting figures of which the shape was like a truncated cone. Therefore, it was concluded that the perturbations were nucleated at the sharp edge where the side face and the larger plane of the figures intersected. This conclusion was supported by the observation of internal melting figures at grain boundaries where their periphery was always sharp.

An examination is made of the Lliboutry theory of glacier sliding. It is concluded that this theory is incompletely developed and therefore it is impossible at present to make meaningful predictions of the sliding velocity from it that might be compared with field data.

Massive calving of the Ward Hunt Ice Shelf, northern Ellesmere Island, occurred between August 1961 and April 1962. An estimated 596 km.2 of ice shelf with a volume of 18 to 24 km.3 became detached to form ice islands, five of which are very large with areas ranging from 70 to 140 km.2. The fracture pattern and the subsequent drift of these ice islands are discussed.

Ice-sheet flow solutions commonly adopt a simple isotropic viscous law, in which the deviatoric stress is coaxial with the strain rate, and the single response function depends on only one invariant, the second principal invariant of the deviatoric stress. This can be correlated with single-stress component tests, which cannot, however, verify the validity of the simplification. Morland (2007) has shown how combined compression and shear tests can verify and correlate a general quadratic isotropic viscous relation, or simply third invariant dependence, and there is evidence that at least third principal invariant dependence is required. Morland (2007) showed that a significant quadratic term changes the relative stress magnitudes in the reduced model for ice-sheet flow, that crucial simplifications are not achieved and formally noted that dependence on the third invariant in the coaxial relation also prevented the simplification. It is now shown that, provided the third invariant dependence does not dominate the isotropic relation, further asymptotic expansion does yield the reduced model simplification, and the influence of different weightings of third invariant dependence is illustrated by a comparison of steady radial flow solutions over a flat bed. It is found that the third invariant dependence does not have a large influence in these examples.

The traditional method of calculating glacier outflows by measuring velocities and areas is difficult, inaccurate and sometimes dangerous in fast mountain streams. The salt-dilution method offers a more accurate alternative but, until now, its use has been restricted because of the difficulty of mixing chemical solutions and measuring chemical concentrations in the field. A computer program has been written which uses a laptop microcomputer to control measurements of stream conductivity and which quickly computes the stream flow directly in the field. The development of this method is described and examples are presented of the application of the method for glaciers in the Rocky Mountains and the Coast Mountains of Canada.

The velocity of flow of a glacier was measured at two places where the ice margin had no moraine debris between clear ice and unfragmented rock. In one of these places the point at which the measurement was made was only about 1 m. from the solid rock. It was found that at both sites the ice was flowing past the rock at a velocity of the same order of magnitude as the velocity of flow in the centre of the glacier in this region. Although conditions at the side of a glacier are not the same as at the bed, this large amount of slip is evidence for a high rate of slip all along the ice-rock interface, and this is in accordance with current ideas of the flow of ice below ice falls.

Surface strain-rate is best observed by fitting a strain-rate ellipsoid to the measured movement of a stake network, or other collection of surface features, using a least-squares procedure. Error of the resulting fit varies as (LΔt√n)-1 where L is the stake separation, Δt is the time period between initial and final stake survey, and n is the number of stakes in the network. This relation suggests that, if n is sufficiently high, the traditional practice of re-visiting stake-network sites on successive field seasons may be replaced by a less costly single-year operation. A demonstration using Ross Ice Shelf data shows that reasonably accurate measurements can be obtained from 12 stakes after only four days of deformation. The least-squares procedure may also aid airborne photogrammetric surveys in that reducing the time interval between survey and re-survey could permit better surface-feature recognition.

The wave of cold temperature, which begins to propagate into a snow field during the winter, may be considerably enhanced by the thermal blanketing of snow accumulating on the surface. This effect is discussed theoretically by means of calculations based on the mathematical theory of the conduction of heat in solids. The results of these calculations show that for an assumed steady velocity of accumulation at the rate of 4 meters/year or 8 meters/year, the winter cold wave should assume significantly larger proportions than in the absence of accumulation.

Two flood waves from the terminus of Peyto Glacier occurred as a result of very high precipitation in early July 1983 and a landslide which exposed a large section of ice-cored moraine. The flood waves induced erosion, and subsequent melt, of the moraine and deposited an estimated 6000 m3 of gravel in the valley. The majority of the deposition occurred in an area approximately 200 m × 20 m to depths of 3 m at the site of the National Hydrology Research Institute gauging station 1 km from the glacier terminus. The initial flood washed away most of the equipment from the site and the gravel deposition totally destroyed the rest of the installation. These events appear to be unique in the period that hydrological records have been maintained for Peyto Creek.

A summary of the winter conditions at the edge of the pack ice around Antarctica, as observed on 16 occasions by the R.R.S. Discovery II between 1932 and 1951, is followed by a more detailed account of each visit. The state of the ice on the northern fringe of the pack is noted especially with reference to the various stages in the formation of pack ice. Detailed reference is also made on each occasion to the meteorological conditions obtaining not only during the ship’s stay on the ice edge but for 2 or 3 days beforehand. Despite the limited number of observations possible it would appear that the state or condition of the ice edge, at any one point in winter, is Iargely dependent on local weather conditions, and it is suggested that, basically, the condition of the ice edge falls into three or, possibly four main categories.

Attention is drawn to the possible relationship between the sea surface temperature and the condition of the ice on the fringe of the pack but it is considered probable that the surface temperature has a greater effect on the distribution of pack ice generally, rather than on the state of the ice edge locally.

To understand snow structure and snowmelt timing, information about flows of liquid water within the snowpack is essential. Models can make predictions using explicit representations of physical processes, or through parameterization, but it is difficult to verify simulations. In situ observations generally measure bulk quantities. Where internal snowpack measurements are made, they tend to be destructive and unsuitable for continuous monitoring. Here, we present a novel method for in situ monitoring of water flow in seasonal snow using the electrical self-potential (SP) geophysical method. A prototype geophysical array was installed at Col de Porte (France) in October 2018. Snow hydrological and meteorological observations were also collected. Results for two periods of hydrological interest during winter 2018–19 (a marked period of diurnal melting and refreezing, and a rain-on-snow event) show that the electrical SP method is sensitive to internal water flow. Water flow was detected by SP signals before it was measured in conventional snowmelt lysimeters at the base of the snowpack. This initial feasibility study shows the utility of the SP method as a non-destructive snow sensor. Future development should include combining SP measurements with a high-resolution snow physics model to improve prediction of melt timing.

The interior of an ice sheet consists of layers of accumulated snow, which contain important information on accumulation and ice dynamics that are imprinted on layer shapes over time. This work describes how changes in accumulation influence the stratigraphy of an ice sheet. The thickness of each layer at present day depends both on accumulation and on the effect of dynamic thinning after its deposition. An isochronal numerical model is used to simulate the evolution of a 2-D, idealized ice sheet while explicitly representing the layers. A series of simulations was carried out to quantify the changes that anomalous accumulation at different locations and times has on the stratigraphy. These simulations form the basis of a linear response function. A second set of simulations with more sustained changes in accumulation is then used to describe large-scale and long-term impacts on the layering of the ice sheet as well as to test the quality of the linear approximation. The aim is to examine whether long-term effects can be extrapolated from small differential changes. The result confirms a certain degree of linearity between changes in accumulation and layer thickness that may be exploited for future inverse modeling applications.

We present seismic measurements of the firn column at Korff Ice Rise, West Antarctica, including measurements of compressional-wave velocity and attenuation. We describe a modified spectral-ratio method of measuring the seismic quality factor (Q) based on analysis of diving waves, which, combined with a stochastic method of error propagation, enables us to characterise the attenuative structure of firn in greater detail than has previously been possible. Q increases from 56 ± 23 in the uppermost 12 m to 570 ± 450 between 55 and 77 m depth. We corroborate our method with consistent measurements obtained via primary reflection, multiple, source ghost, and critically refracted waves. Using the primary reflection and its ghost, we find Q = 53 ± 20 in the uppermost 20 m of firn. From the critical refraction, we find Q = 640 ± 400 at 90 m depth. Our method aids the understanding of the seismic structure of firn and benefits characterisation of deeper glaciological targets, providing an alternative means of correcting seismic reflection amplitudes in cases where conventional methods of Q correction may be impossible.

The Swiss rutschblock test provides practical information about the stability of snow slabs. However, its use by avalanche workers and ski guides is limited by the time required to perform the test and recommended minimum slope inclination (30°). The present study shows how time requirements can be reduced by cutting rutschblocks with cords or specialized saws — faster techniques that do not appear to affect the results. Comparing the rutschblock results with a stability index developed in Switzerland shows that the recommended minimum slope inclination can be reduced to 20°, provided a second person is present to observe the small block displacements associated with slope inclinations below 30°. Sets of rutschblocks on slopes that vary in inclination by 8° or more are used to determine the effect of slope inclination on rutschblock scores. Also, the frequency distributions of six large sets of repeated tests are used to estimate the precision of one or two tests on a uniform slope.

The fluorescent dye dilution method for determining the liquid-water content in snow is based on measuring the concentration change of a solution when it is mixed with snow. Samples for analysis can be obtained rapidly and reliably, and, unlike calorimetric or equilibrium-temperature methods, field use requires no on-site data analysis.

To better constrain meltwater transport and ice viscosity in temperate glaciers, particularly in ice stream shear margins, we use a custom permeameter to study the untested model relationship between the permeability of temperate ice and its liquid water content. The permeability of lab-made ice of two mean grain diameters (1.8 and 4.2 mm) is measured, and water content is controlled with the ice salinity and measured calorimetrically. Fluorescein dye is added to through-flowing, chilled water to highlight flow pathways through the ice after experiments. As predicted by a simple model, permeability increases with approximately the square of the water content and by about three orders of magnitude across water contents of 0.1–4.4%. However, permeability values are less than those of the model by average factors of 2.6 and 4.1 for the finer and coarser ice, respectively. This discrepancy is likely due to tortuous, truncated or air-clogged veins. The order-of-magnitude agreement between measured and modeled values may indicate that reduced permeability from these factors is nearly compensated by preferential flow in oversized veins that are isolated or arborescent. Both kinds of preferred flow pathways are observed but the latter only in fine-grained ice at water contents > 2%.

Strain-rate and surface velocity measurements were made on a valley glacier. The measured strain-rates were used to calculate the stress condition and velocity distribution in the glacier. The measured velocity is in reasonable agreement with that calculated from Nye’s plasticity solution.