White Glacier, 1996; Thompson Glacier lies beyond lateral moraine

White Glacier, 1980; Thompson Glacier at right, Between Lake at upper right; White Glacier Hill at left
White Glacier is a valley glacier occupying 38.7 km2 in the Expedition Fiord area of Axel Heiberg Island, Nunavut, Canada (longitude -90°50', latitude 79°30'). It extends in elevation from 56 m to 1782 m above sea level, a range which, as noted by Dyurgerov (2002), is exceeded only by Devon Ice Cap in the world list of glaciers with measured mass balance. Sea-level temperature in the Expedition Fiord area averages about -20°C, but the glacier is known to have a bed which is partly unfrozen, at least beneath the valley tongue; ice thickness reaches or exceeds 400 m. Annual precipitation at sea level is very low, about 100 mm a-1. However annual accumulation at higher altitudes is greater, reaching 370 mm a-1 at 2000 m on Müller Ice Cap to the north of White Glacier. Annual ablation at the terminus of the glacier is typically 2000-4000 mm a-1. The equilibrium-line altitude averages 970 m, with a range from 470 m to 1400 m, and mass balance is well correlated with equilibrium-line altitude.

In the photograph, note the irregular terrain in front of the glacier terminus. This is White Glacier's terminal and recessional moraine. Its maximum extension, marking the advance of the glacier in response to the cooling of the Little Ice Age, was reached not earlier than the late 18th century, and more probably at the beginning of the 20th century. The amount of retreat to the date of the photograph, 1980, is about 400 m, and since then there has been another 100 m of recession. There is now evidence that the retreat of the terminus, previously at about 5 m a-1, is decelerating (Cogley et al. 1996a; Cogley and Adams 2000). However, the advance of the adjoining Thompson Glacier continues; the two terminuses have been in contact since at least the time of the earliest photographs in 1948, but, although they remain distinguishable, White Glacier has become a tributary of Thompson Glacier.

Contact between White Glacier (left) and Thompson Glacier (right)
Photo credit: Rob Hember
The mass-balance record of White Glacier has most recently been reassessed by Cogley et al. (1995, 1996b). The mass-balance "normal", for 29 years of record from 1960 to 1991, was -100±48 mm a-1, with extreme annual values of -780 mm a-1 and 350 mm a-1. No statistically significant trend can be found in the mass-balance series, but a principal finding of the reassessment is that physically plausible values of trend would not be detectable with current stake-based methods of measurement: errors in estimates of annual mass balance are of the order of 200-250 mm a-1. However the average balance during the 1990s, -278±126 mm a-1, was the most negative of the four decadal averages now available.

On the other hand, in 1998 White Glacier's mass balance was -229 mm a-1, slightly above the decadal average. This year, globally, was the warmest since weather records began and very probably the warmest of the last millennium (Houghton et al. 2001). It was also the year of most negative mass balance in the much shorter global glaciological record (see Global Glaciology) - but evidently not on Axel Heiberg Island.

White Glacier has been the subject of many papers in the glaciological literature since 1960 (Ommanney 1987; Cogley 1999a). A recent example is Cogley (1999b). Notable earlier studies include those of Blatter (1987) and Müller (1962). The latter was the source of a now-classical diagram elaborating and illustrating the concept of "glacier facies".


References
Saxifraga oppositifolia - purple saxifrage
Blatter, H., 1987, On the thermal regime of an arctic valley glacier: a study of White Glacier, Axel Heiberg Island, N.W.T., Canada, Journal of Glaciology, 33, 200-211.

Cogley, J.G., 1999a, Axel Heiberg Island: Selected References on Glaciology, Trent Technical Note 99-2, Department of Geography, Trent University, Peterborough. 9p.

Cogley, J.G., 1999b, Effective sample size for glacier mass balance, Geografiska Annaler, 81A(4), 497-507.

Cogley, J.G., W.P. Adams, M.A. Ecclestone, F. Jung-Rothenhäusler and C.S.L. Ommanney, 1995, Mass Balance of Axel Heiberg Island Glaciers, 1960-1991 -- A Reassessment and Discussion, Science Report 6, National Hydrology Research Institute, Environment Canada, Saskatoon. 178p.

Cogley, J.G., M.A. Ecclestone and W.P. Adams, 1996a, Fluctuations of the terminuses of White and Thompson Glaciers, Axel Heiberg Island, Eastern Snow Conference Proceedings, 53, 83-94.

Cogley, J.G., W.P. Adams, M.A. Ecclestone, F. Jung-Rothenhäusler and C.S.L. Ommanney, 1996b, Mass balance of White Glacier, Axel Heiberg Island, N.W.T., Canada, 1960-91, Journal of Glaciology, 42, 548-563.

Cogley, J.G., and W.P. Adams, 2000, Photographic resources for monitoring glacier fluctuations on Axel Heiberg Island, Arctic, 53(3), 248-259.

Dyurgerov, M.B., 2002, Glacier Mass Balance and Regime: Data of Measurements and Analysis, Occasional Paper 55, Institute of Arctic and Alpine Research, University of Colorado. 268p. Boulder, Colorado.

Houghton, J.T., and 7 others, 2001, Climate Change 2001: The Scientific Basis. Cambridge University Press, Cambridge. 881p.

Müller, F., 1962, Zonation of the accumulation area of the glaciers of Axel Heiberg Island, N.W.T., Journal of Glaciology, 4, 302-310.

Ommanney, C.S.L., 1987, Axel Heiberg Island bibliography. In Occasional Paper 12, 5-55, Department of Geography, Trent University, Peterborough, Canada. (Also Miscellaneous Paper 2, Axel Heiberg Island Research Reports, McGill University, Montreal.)