Temperature measurements in a subpolar surge-type glacier reveal a distinctive thermal structure associated with the boundary between the ice reservoir and receiving areas. In the receiving area the glacier is cold based, but bottom temperature has increased as much as 0.5 °C between 1981 and 1982, and the basal heat flux is roughly 10 times the expected geothermal flux. Water percolation through permeable subglacial material is the probable energy source. Deformation of the substrate could destroy this drainage system and trigger a surge.

Glaciers can be divided into two classes according to their flow behavior: normal (relatively steady annually averaged flow rate) and surge-type (pronounced cyclic flow variations having a typical periodicity of 10-100 years). We have examined the population statistics of 2356 glaciers in the St. Elias Mountains, Yukon Territory, Canada, and estimate that 151 (6.4%) of these glaciers are surge-type. To explore how various glacier attributes are associated with surging, we compare the probability of surging associated with various subsets of the complete population to appropriate reference values. In this way, potential influences on surge tendency can be examined. For the 55 drainage basins analyzed, there is a pronounced spatial variation in the concentration of surge-type glaciers, but no obvious environmental control can be evinced. Within the study area the greatest concentration lies in the northern St. Elias Mountains, a region of high topographic elevation that is experiencing rapid tectonic uplift. Analysis of the influence of length on surge tendency reveals that long glaciers have a significantly greater probability of being surge-type than short glaciers. The surge probability increases monotonically from 0.61% for very short glaciers (0-1 km) to 65.1% for long glaciers (10-75 km). This result suggests that ice sheets and ice caps, or at least portions of them, should have a high probability of surging. Tributary glaciers have a greater tendency to surge than trunk glaciers, presumably because they may themselves be surge-type and may additionally participate in surges of the trunk glacier. The nonrandom geographical distribution of surge-type glaciers is not simply a consequence of the variation from basin to basin of the glacier length distribution. Surge-type glaciers tend to have a higher overall elevation than normal glaciers: the elevation of the highest point of the accumulation zone, the elevation of the snow line, and the elevation of the lowest point of the ablation zone, on average, exceed the corresponding elevations for normal glaciers. There is no significant difference between the overall slopes of surge-type and normal glaciers, although there is a tendency for surge-type glaciers to have greater slope in the accumulation zone and lesser slope in the ablation zone than normal glaciers. Although the prevalent flow direction for glaciers in the Yukon data set is to the north, surge-type glaciers tend to flow to the east and southeast. This orientation influence is probably explained by the fact that many of the longest glaciers also flow to the east and southeast. Papernumber 5B5680. 0148-0227/86/005 B 5680505.00 fled 204 surge-type glaciers in western North America, and all are located in the mountain ranges of Alaska, Yukon Territory, and northwestern British Columbia, the majority being s•tuated in the St. Elias Mountains near the Alaska Yukon border. No surging glaciers are found in ranges to the south such as the Coast Mountains, the Selkirk Mountains, and the Rocky Mountains. Other ...

A study of the movement of Rusty Glacier was undertaken and continued through four summers because it is believed to be a surging glacier in the last stages of the inactive phase preceding a surge. The entire glacier is very slow moving, essentially motionless in the lower third and most rapid in an area well above the firn line. Unusually steep flow-line emergence angles and higher than average longitudinal compression rates in the lower–middle part of the glacier indicate gradual thickening of the ice above the stagnant lower tongue. There is no clear correlation between local variations in flow rates and surface or bottom topography. The glacier is mostly colder than 0° C to the bottom, and in the one known area of 0° C bottom temperature, flow rates are not greater than elsewhere. Although the glacier is everywhere very thin, maximum flow rates seem clearly related only to variations in ice thickness. The nearby Trapridge Glacier is also a surging glacier and exhibits a strikingly similar flow pattern.

ABSTRACT. A survey was made in 1974 of the small lake which had formed as a result of the surge advance of Steele Glacier, Yukon Territory, in 1965-68. Maximum lake level is controlled by a drainage channel which passes over rock near the hydrologic left margin of Steele Glacier. Since the surge advance of 1965-68 the lake has twice drained subglacially, producing minor outburst floods on Steele Creek and increasing the discharge of the Donjek River which crosses the probable route of the Alaska Highway pipeline.RÉSUMÉ. Histoire et bathymétrie d'un lac formé par une crue exceptionnelle d'un glacier formant barrage. On fit une étude, en 1974, du petit lac qui s'était formé à la suite d'une crue exceptionnelle, en 1965-68, du glacier Steele, dans le Territoire du Yukon. Le niveau maximum du lac est contrôlé par un canal de drainage qui passe par-dessus un tcrrain rocailleux non loin du bord hydrologique gauche du glacier Steele. Depuis la crue exceptionnelle de 1965-68, le lac s'est drainé par deux fois au-dessous de la couche de glace, occasionnant des crues subites peu importantes du Steele Creek et augmentant le débit du Donjek River qui traverse le parcours proposé pour la pipeline de la Route de l'Alaska.

As part of a program to study surge-type glaciers, a radar-depth survey, using a frequency of 620 MHz, has been made of Trapridge Glacier, Yukon Territory. Soundings were taken at 26 locations on the glacier surface and a maximum ice thickness of 143 m was measured. A rapid change in surface slope in the lower ablation region marks the boundary between active and stagnant ice and is suggestive of an “ice dam” or the water “collection zone” postulated by Robin and Weertman for surging glaciers.