In an effort to ascertain the drainage mechanism of ice-dammed self-draining lakes, the author made observations on the behavior of the small Casement Glacier Lake in 1967. On 22 July when the first outburst of the lake occurred the water level dropped 31.92 m, leaving approximately 35 m of water remaining. Then, following a 2 week period of stability, the lake level fell gradually but steadily during the rest of the summer. Whereas a second rapid discharge occurred in 1965, one never did in 1967. The initial discharge was subglacial and resulted from flotation of the dam; the slow late-summer drainage, however, cannot be attributed to that mechanism and thus remains to be explained.

Soil temperatures were recorded over periods of several weeks in the years 1909 and 1970 in two sites to a depth of 100 cm. It was found that snow depth was of major importance in the rate of freezing of the soil in winter; where snow cover was less than 5 cm in depth freezing rates were almost double those where snow depth was over 1 m. Snow cover also insulated the soil surface from above-zero air temperatures during spring, and soil thawing commenced from the surface only following the clearance of snow. Similarly, insulation of the soil surface by snow prevented short-term freezing and thawing cycles penetrating the soil, although even where snow cover was absent such short-term cycles were not observed to penetrate the soil to depths in excess of 5 cm. This surficial freezing and thawing of the soil took place more readily in spring than in the autumn. It was concluded that the annual cycle of soil freezing and thawing was the dominant factor in the thermal regime of these soils, short-term freezing cycles affecting only the immediate surface soil layers.

Empirical glacier mass-balance models are commonly used in assessments of glacier and runoff evolution. Recent satellite-borne geodetic mass-balance observations of global coverage facilitate large-scale model calibration that previously relied on sparse in situ observations of glacier mass change. Geodetic observations constitute temporally aggregated mass-balance signals with significant uncertainty, raising questions about the role of observations with different temporal resolutions and uncertainties in constraining model parameters. We employ a Bayesian approach and demonstrate the sensitivity of parameter values to commonly used mass-balance observations of seasonal, annual and decadal resolution with uncertainties characteristic to in situ and satellite-borne observations. For glaciers along a continentality gradient in Norway, the use of annual mass balances results in around 20% lower magnitude of modelled ablation and accumulation (1960–2020), compared to employing seasonal balances. Decadal mass balance also underestimates magnitudes of ablation and accumulation, but parameter values are strongly influenced by the prior distribution. The datasets yield similar estimates of annual mass balance with different margins of uncertainty. Decadal observations are afflicted with considerable uncertainty in mass-balance sensitivity due to high parameter uncertainty. Our results highlight the importance of seasonal observations when model applications require accurate magnitudes of ablation, e.g. to estimate meltwater runoff.

Thermograph, thermistor, and thermometer readings at a 30 m. deep bergschrund from June 6 to July 22, 1953, showed that there was little direct relationship between air temperatures outside and at the bottom of the Schrund. The air temperature inside ranged from −3.7° C. (253° F.) to +0.5° C. (32.9° F.), but from July 2 onwards it oscillated between –0.5° C. and +0.5° C., with a 3–4 day periodicity. The ice temperature at the bottom of the schrund behaved similarly, though it was about 0.5° C. colder. The oscillations may have been caused by the interplay of flowing melt water (source of heat) and air drainage in quiet weather (source of cold). The granite-gneiss headwall, where not sheathed by refrozen melt water, appeared to be chemically and mechanically unweathered, which supported the conclusions of Battle’s earlier tests in deep bergschrunds and in the laboratory.

Annual net balance eight North Cascade glaciers during the 1984-94 period has been determined by measurement of total mass loss firn and ice melt and ice melt and, residual snow depth at the end of the Summer season. Overall spatial density of measurment points is 200 points km−2. Mean annual balance of North Clascade glaciers from 1984 to 1994 has been −0.38 ma−1. The resulting 4.2 m loss in water-equivalent thickness is significant, since North Cascade glaciers have an average thickness of 30–50 m.

Cross-correlation of annual net balance Ior eight glaciers ranges from 0.83 to 0.97. This indicates the mass balances of the eight glaciers have been responding similarly to elimate conditions despite their range of topographic and geographic characteristics. Annual net balance of individual glaciers was correlated with climate records. The highest ablation-season correlation coefficient is mean May–August temperature, ranging from 0.63 to 0.84. The highest accumulation-season correlation coefficient is total accumulation-season precipitation, ranging from 0.35 to 0.59.

A simulation process model is developed for rating avalanche danger for twelve east-facing avalanche paths loaded by westerly winds. The model simulates layer age and densification, snow depth, snow transport and deposition, formation of melt crusts, snow temperatures, temperature gradient metamorphism, and avalanche danger on a 6 h basis. Conditioned on avalanches alone, the model predicted avalanche potential on 86% of the 175 avalanche days during an eight-year period. It indicated avalanche potential 50% of the time on non-avalanche days. A sensitivity analysis is under way to improve model performance, and simulation of danger from additional avalanche samples is planned.

The upper 180 ft. (55 m.) of Lake Vanda in Wright Valley, south Victoria Land, is essentially potable, whereas that part below 200 ft. (61 m.) is more than three times as saline as sea-water. The salinity below 200 ft. (61 in.) resulted from the evaporation and freezing, mainly during interglacial (Loop-Trilogy) time, of a larger, less saline body of water.

An alluvial fan in Wright Valley has been dated as interglacial on the basis of (1) ice-marginal channels formed in Loop time that cut across it, and (2) the fjord-like longitudinal cross-section of the valley formed by the ice of the oldest glaciation or glaciations.

Fossils found in till and glacio-fluvial deposits in the McMurdo Sound region, south Victoria Land, date from both early and late Pleistocene interglacial time.

An ocean-bottom core sample obtained in the Ross Sea contained interglacial material. The presence in the sample of glacial marine sediments deposited in interglacial time suggests that the Antarctic Ice Sheet maintained itself throughout the Pleistocene.

Sub-surface efflorescences consisting of a layer of pure salts as much as 3 in, (7.6 cm.) thick are found 2−5 in. (5−13 cm.) below the surface in Loop deposits in Wright Valley. The absence of similar thick occurrences in Trilogy deposits indicates that the efflorescences are, in part at least, interglacial.

Interglacial cinder cones and lava flows are found in the McMurdo Sound area, and some of the widespread scoria present in moraines, glacio-fluvial deposits and beaches dates from interglacial time.

Application of thermal convection theory to polar ice sheets (Hughes, 1970, 1971. 1972[a],[c]) is reviewed and expanded. If it occurs, thermal convection is mainly concentrated near the bed of the ice sheet; resulting in active and passive convective flow, respectively below and above the ice density inversion. Convection begins as transient creep when a stress-independent critical Rayleigh number is exceeded, and stabilizes as steady-state creep when a stress-dependent critical Rayleigh number is exceeded. Transient- creep convection begins as unstable ripples in isotherms near the bed, with some ripples becoming upward bulges of basal ice which rapidly shrink laterally and grow vertically to become ascending dikes of recrystallized basal ice during steady-state creep. Sills of basal ice are injected horizontally between weakly coupled layers in the strata of cold ice slowly sinking en masse between dikes. Convection begins under domes of thick ice toward the ice-sheet center and a stable polygonal array of dikes may form if frictional heat creates hot ice at the bed as rapidly as convection flow redistributes hot basal ice in dikes and sills, Advective flow transports the converting ice toward the margin of the ice sheet where dikes converge at the heads of ice streams. Dike—sill convection then becomes ice-stream convection in which the entire ice stream behaves like a dike, uncoupling from the bed, and rising en masse. This would help explain why ice streams flow at surge velocities.

The long-term monitoring of Lewis Glacier on Mount Kenya serves as a basis for the study of glacier evolution in response to climatic forcing through modeling of its ice flow and mass budget. Following up on an earlier modeling and prediction study to 1990, this paper examines the ice-mass and flow changes in relation to the net-balance conditions over 1986–90. A model experiment using as climatic forcing the observed 1978–86 vertical net-balance profile yielded a volume loss and slow down of ice flow more drastic than observed during 1986–90. The causes of this discrepancy were examined in successive model experiments. Realistic simulations of mass-budget and thickness changes over 1986–90 are obtained using as input the net-balance forcing for the same period rather than for the preceding 1978–86 interval, and approximate flow velocities. With the same net-balance forcing and a completely stagnant Lewis Glacier, the elimination of mass redistribution by ice flow acts to mitigate the loss of volume and thickness in the upper glacier, and to accentuate it in the lower glacier. Accordingly, the observed 1986–90 net-balance profile along with the 1990 ice-flow velocities provide suitable input for the modeling of Lewis Glacier changes to 1994. Under continuation of the 1986–90 climatic forcing, ice thinning ranging from less than 1 m in the upper glacier to more than 7 m in the lower glacier, and a total volume loss of order 57 × 104 m3, are anticipated over the 1990–94 time interval.

Conduit and regelation water are inferred to drain as ground water from up to 130 km2 of Columbia Icefield. Subglacial conduits appear to be generally occupied by free surface streams. Ground-water flow will allow exchange between the regelation film and conduits. Present-day discharge from beneath the accumulation zone carries little sediment, and past injections of sediment appear to correspond to ancient interglacials. Transport of sediment through cave passages may be analogous to transport through basal conduits.

It is suggested that both discontinuous shearing and continuous flow (creep) may coexist in one and the same glacier, provided the stress is high enough for the shear resistance to be reached. Experiments made in a tunnel in the Z’Mutt Glacier suggest that all the motion here observed was continuous, and also show that the viscosity is influenced by the stress conditions. A series of tests made by forcing a ball into the ice also enabled estimates of the viscosity and melting pressure to be made and emphasized the importance of melting in glacier flow.

The steady profile of a finite-amplitude kinematic wave on a glacier is calculated with the assumption that the wave velocity varies linearly with h1, the departure of the ice thickness from the datum state. If the flow of ice is due mainly to sliding of the glacier on its bed, the width of the calculated steady profile is several hundred times the datum state ice thickness. The width of an observed kinematic wave front on Nisqually Glacier, Mt. Rainier, Washington is at least an order of magnitude smaller than the calculated steady profile. This indicates that the observed steepening of the wave may be due to effects other than variation of wave velocity with ice thickness.

In Southeast Greenland, summer melt and high winter snowfall rates give rise to firn aquifers: vast stores of meltwater buried beneath the ice-sheet surface. Previous detailed studies of a single Greenland firn aquifer site suggest that the water drains into crevasses, but this is not known at a regional scale. We develop and use a tool in Ghub, an online gateway of shared datasets, tools and supercomputing resources for glaciology, to identify crevasses from elevation data collected by NASA's Airborne Topographic Mapper across 29000 km2 of Southeast Greenland. We find crevasses within 3 km of the previously mapped downglacier boundary of the firn aquifer at 20 of 25 flightline crossings. Our data suggest that crevasses widen until they reach the downglacier boundary of the firn aquifer, implying that crevasses collect firn-aquifer water, but we did not find this trend with statistical significance. The median crevasse width, 27 meters, implies an aspect ratio consistent with the crevasses reaching the bed. Our results support the idea that most water in Southeast Greenland firn aquifers drains through crevasses. Less common fates are discharge at the ice-sheet surface (3 of 25 sites) and refreezing at the aquifer bottom (1 of 25 sites).

A power law relation between stress and strain rate of the form was used to describe the response to strain rate of S1 ice loaded across the columns at –10° C. The rate exponent, n, decreased with increasing strain from about 4.6 at an observed peak on the load displacement curve to approximately 2.6 at a shortening of 2%. Analysis of these results and of the results of other authors on different forms of ice deformed at the same temperature suggests that the power law exponent, n is proportional to Fc/Fg The parameter Fc/Fg is the far-field basal dislocation climb force divided by the glide force.

Glaciar Yanasinga (lat. 11° 36′ S., long. 76° 12′ W., 4850 m a.s.l.) is probably one of the few glaciers in the equatorial region on which measurements have been performed during the last 24 years. These were carried out in the years 1944, 1945, 1946, 1947, 1948, 1949, 1957, 1963 and 1968. The results of these surveys are presented on a map and references are given for those interested in obtaining more detailed information.