A model, relating spatial patterns of snow accumulation in the alpine belt of major mountain ranges to the angular relationship which exists among terrain features such as cirque basins, mean storm-path trajectories, and incident solar radiation, is presented together with a limited amount of relevant empirical data. It is suggested that an “orientation gradient” exists in both the temporal and spatial variation of accumulation and ablation in the alpine terrain, the importance of which varies as some function of the relative control exerted by wind redistribution of snow and of direct incident solar radiation on the accumulation and ablation processes. The data obtained to date suggest that the importance of the orientation gradient varies widely among the mountain ranges studied, being a good predictor of snow distribution patterns in the Front Range of the Colorado Rockies and the Snowy Range in southern Wyoming, both of which are relatively windswept, while in the much less windy Bridger Range, in south-western Montana, both orientation and elevation appear to contribute on an almost equal basis. An indirect method of estimating relative amounts of annual mass turnover, using eleven glaciers located in the Wind River of west central Wyoming, is presented.

Equations are derived, using a total potential-energy formulation, which predict the wavelength of the dominant wave pattern of a flowing snow slab. Account is taken of the visco-elastic properties of an assumed surface layer of snow which overlays a distinct visco-elastic foundation layer of snow. The predicted wave pattern is recognized as a precursory mechanism which influences the characteristics of the sawtooth flank fracture pattern that may remain following a snow avalanche, particularly on broad, uniform slopes. The parameters that influence the wave pattern are determined by an order-of-magnitu de reduction of the terms in the governing differential equation for visco-elastic slab response.

Inclinometry with embedded probes is analyzed with a Stokes model of a solid body floating in a fluid with much smaller viscosity for a two-dimensional flow field. The assumption that such a probe behaves like a Lagrangian unit vector is only justified for probes embedded in a Newtonian fluid with lengths at least four times their width. A fluid with Glen-type rheology results in a slightly smaller rotation rate of the probe compared to Newtonian fluids.

The hypothesis that ice-sheet evolution is only controlled by the long-term non-Newtonian viscous behavior of ice has been challenged by observations indicating that effects like brittle failure, stick-slip sliding, tides and wave action may affect ice-sheet evolution on sub-daily timescales. Over these timescales, the quasi-static-creep approximation is no longer appropriate and elastic effects become important. Simulating elastic effects in ice-sheet models over relevant timescales, however, remains challenging. Here, we show that by including a visco-elastic rheology and reintroducing the oft neglected acceleration term back into the ice-sheet stress balance, we can create a visco-elastic system where the velocity is locally determined and information propagates at the elastic wave speed. Crucially, the elastic wave speed can be treated like an adjustable parameter and set to any value to reproduce a range of phenomena, provided the wave speed is large compared to the viscous velocity. We illustrate the system using three examples. The first two examples demonstrate that the system converges to the steady-state viscous and elastic limits. The third example examines ice-shelf rifting and iceberg calving. This final example hints at the utility of the visco-elastic formulation in treating both long-term evolution and short-term environmental effects.

Ice originating near the inland ice divide of the ice sheet can reappear as marginal ice at the surface near the ice terminal in the ablation area. We have analyzed δ18O values and ion concentrations of the Skallen, Skarvsnes and Hamna terminal ice sections, located along the estuary line in the Sôya drainage basin, East Antarctica. The data suggest that the upper part of the Skallen terminal ice section could have originated from inland precipitation on the Shirase drainage basin during marine isotope stage (MIS) 5e, while the upper part of Skarvsnes and Hamna terminal ice sections could have originated from inland precipitation on the Sôya drainage basin. We calculate past elevation maps for the Antarctic ice sheet using the three-dimensional model, SICOPOLIS. This model suggests that the upstream portion of the Sôya drainage basin during the glacial period (MIS 2, 3 or 4) was located to the northeast of its present location. A flow history is proposed wherein ice from the inland Shirase drainage area flowed over the present ice-divide line from the Shirase to the Sôya drainage basin during the glacial period. The ice in the Sôya drainage basin then flowed to the marginal part of the sheet after the ice divide had assumed its present position.

The shape of the former Laurentide ice sheet in what is now northern Ohio and southern Ontario is calculated and the subglacial hydrological potential field computed. Subglacial water flow is found to be concentrated over high points in the bed, such as what is now Kelleys Island in Lake Erie. Some 1010 litres of subglacial melt water per year passed over Kelleys Island.

It is argued that the “glacial” grooves on Kelleys Island are subglacial melt-water channels. Assuming that the subglacial melt water attained saturation with respect to CaCO3, in passing over the limestone of Kelleys Island, the material formerly occupying the grooves could have been dissolved in 102 years. This is a much shorter time than glacier occupancy and the assumption of chemical equilibrium is not critical.

The features on Kelleys Island are fluted valleys about 6 m across and each flute is about 0.1 m in width. Each flute represents a subglacial channel but only one or two of these channels operated at any one time. Blockages, perhaps caused by basal debris, caused the rivers to make minor course changes and in many instances it is possible to determine the order of channel occupancy. The channels were striated after abandonment by water when moving basal debris or debris-laden ice occupied the channels. From the Gauckler-Manning formula and the potential gradient obtained from the ice-sheet model the river velocity is calculated to be about 4 m s–1, in rough agreement with the water flux calculated earlier.

The grooves support the concept that subglacial water flows in “Nye” channels, and raise the suggestion that subglacial erosion by solution is of widespread importance.

An analysis is made of the rate of bubble coalescence in an ice mass that is deforming. A total strain of at least 8 is required before appreciable coalescence occurs. The analysis has been applied to deforming ice shelves and ice sheets. No appreciable coalescence is expected in ice shelves but coalescence should occur in ice sheets (or glaciers) if the shear strain-rate at the bottom surface is of the order of 0·075/year or larger. Measurements of bubble concentration are capable of setting limits on paleo-strain-rates of the present ice sheets. Bubble migration down temperature gradients presents complications to the study of bubble coalescence.

Single crystals and bicrystals of water ice have been adiabatically pressurized to produce, and clearly illustrate, two types of internal melt figures: (1) dendritic figures that grow from nucleation imperfections on the specimen’s surface, or from air bubbles at grain boundaries, into the ice as pressure is elevated; and (2) compression melt fractures, flat liquid-filled disks, that nucleate at imperfections in the crystal and grow with the application of pressure eventually to sprout dendritic fingers at the periphery. The transparency of the ice permitted visualization of the growth and behavior of the figures, and this could be an important tool in understanding the role of phase transformations in deep-focus earthquakes. Correlation between figure size and pressure is noted for the first time.

Glaciological studies during the Sheffield University Expeditions to Kilimanjaro in 1953 and 1957 included a survey of the glaciers and a close examination of the Penck Glacier and the stagnant remnants of the ice cap on the summit. The Penck Glacier has done little downcutting although it rests on friable rock. The glaciers and summit remnants are rapidly retreating, the Penck Glacier having retreated 3 m. in 3 months in 1957, and nearly 300 m. since 1912. The main accumulation zone appears to be at about 4,500–5,000 m. with a local “low level” firn line and an upper firn line above the top of the mountain. Maps of the glaciers, their recent fluctuations and moraines are being prepared. The glaciological and meteorological observations in 1957 form part of the I.G.Y. programme for East Africa.

During the summer of 1983 a 2 kW array of solar voltaic panels was used to power a drill which collected two cores of 154 m and 163 m length to bedrock on the Quelccaya ice cap in Peru. The operation and performance of this array are discussed, considering the need for future requirements in remote pristine areas of the world.

Computing predictions of future sea level that include well-defined uncertainty bounds requires models that are capable of robustly simulating the evolution of ice sheets and glaciers. Ice flow behaviour is known to be sensitive to the location and geometry of dynamic ice boundaries such as the grounding line (GRL), terminus position and ice surface elevation, so that any such model should track these interfaces with a high degree of accuracy. To address this challenge, we implement a numerical approach that uses the level-set method (LSM) that accurately models the evolution of the ice–air and ice–water interface as well as capturing topological changes in ice-sheet geometry. This approach is evaluated by comparing simulations of grounded and marine-terminating ice sheets to various analytical and numerical benchmark solutions. A particular advantage of the LSM is its ability to explicitly track the moving margin and GRL while using a fixed grid finite-difference scheme. Our results demonstrate that the LSM is an accurate and robust approach for tracking the ice surface interface and terminus for advancing and retreating ice sheets, including the transient marine ice-sheet interface and GRL positions.

Medial moraines and lineations on the surface of composite glaciers enable the detection of structural and hydrological features. A study of the composite glacier Breidamerkurjökull, south Iceland, indicates relationships between subglacial waterways, ice structure in the junction area, and development of the glacier terminus. First, rivers are situated in or near medial moraines because melt water percolates to the bed and moves from there with the subglacial rivers mainly in the direction of ice flow. Secondly, the contact between two feeder glaciers sometimes forms an angle at the glacier terminus. Then the meltwater river escaping from the contact, generally in a radial direction (away from the glacier front), during the retreat will be transferred to the front of the first receding glacier. The drainage of the contact zone then changes from a radial to a tangential direction, destroying the terminal moraines of the recession stages.

Similar relations are found in relics of Pleistocene ice sheets, two examples of which are compared. The huge subglacial channel of the Münsterländer Kiessandzug-Esker below the ice sheet of the Saalian glaciation in the Münsterland, north-west Germany, was formed in the ice-flow direction. It therefore gives details of the morphology and of the great ice-dammed lake east of the Teutoburger Wald ridge. At the contact between the Norwegian and Baltic Sea glaciers, the terminus formed an angle during the maximum extent of the Weichselian glaciation in northern Jutland. During retreat, the Norwegian glacier receded first. The large melt-water river escaping from the contact between both glaciers had formed the huge Karup Sandur during the maximum, but now, during the recession, it changed to the front of the Norwegian ice, destroying the recession moraines there.

An interacting continua framework is adopted to model a dry snow park, which is viewed as a three-constituent mixture composed of an ice matrix whose pore space is occupied by water vapour and dry air. We focus on the response of a one-dimensional vertical snowpack to changes in pressure and temperature at its surface. The time-scale of the surface forcing is assumed to be much longer than the time-scale for thermal transfers and phase change to take place. The constituents are, therefore, in thermal equilibrium with a common temperature Τ which is governed by a single bulk-energy balance. In addition, each constituent satisfies a mass and momentum balance. The constitutive postulates and external prescriptions necessary to close the system of equations are discussed in detail. Non-dimensional variables are then introduced formally to draw out the major balances in the equations and construct a reduced system that accurately models the dominant features in the snowpack. It is shown how the effects of phase change enter the leading-order balance. An iterative procedure is constructed to solve the system. Illustrations for the case of a sinusoidal annual temperature gradient imposed at the surface are presented.

A two-dimensional finite element computer program has been used to compute the elastic stress distribution in realistic multi-layered snow packs. Computations have been done on three-layered and five-layered snow packs intended to simulate conditions on the Lift Gully at Berthoud Pass, Colorado. Calculations have been performed to determine the effect of a layer of new snow and the effect of a weak sub-layer. Stress levels were obtained which are reasonable compared with available snow strength data.