The McCall Glacier Station, Brooks Range, Alaska
Robert W. Mason
Introduction . . .
One of the many contributions of mountaineers to the scientific study of the conditions in which human beings live is the high altitude scientific station or observatory. To the purist, the presence of a hut on a mountain peak and a party of permanent dwellers is a sacrilege. To the same man, unlucky in his judgment and caught in the midst of a summit gale, the little shelter is a haven and a blessing.
Scientific stations located in high alpine country have provided a variety of useful data to the basic study of man’s environment and contributed to his knowledge of the forces that surround him. Such stations have been established to carry out a host of different observations for many purposes. On the Jungfraujoch in Switzerland is one of the best known mountain research stations. Scientists there carry out programs in meteorology, the study of cosmic radiation and glaciology. The station at Davos in Switzerland has emphasized the further understanding of the conditions and forces involved in snow structure and avalanche formation. Less well known, perhaps, to the mountaineer are the high altitude observatory of the National Bureau of Standards in Colorado, and the observatory at Huancayo in Peru where detailed studies in solar activity, cosmic radiation and ionospheric effects are made.
The installations at these stations may be highly complex, like the Mount Wilson Observatory in California, or as simple as the Dartmouth College meteorological station on Mount Washington, New Hampshire. These stations may be permanent in nature, studying long-term trends as well as providing a daily service like the U. S. Geological Survey seismological stations on Kilauea in Hawaii, or they may be stations maintained for a summer or a year to record specific data for a single study like the mountain station established in 1957 on the McCall Glacier in Alaska’s Brooks Range.
Mountain stations are usually specifically established to provide information which contributes to basic research. But in many cases these stations contribute as well to knowledge of alpine areas and assist the mountaineer by providing him knowledge of the environment and conditions into which he may venture. The McCall Glacier Project is an example of just such a mountain station. It is hoped that the information in this article will add to the scant material available about this remote and unfrequented range.
Henry S. Francis, Jr., Chairman, Research Committee
UNTIL the International Geophysical Year no thorough study of the few existing arctic alpine glaciers had been attempted by North American glaciologists. Indeed, the collection of tiny glaciers in northeastern Alaska had received only a brief reference in glaciological literature. For this reason the IGY McCall Glacier Project1 was in many respects as much an exploratory undertaking as the great over-snow traverses of the IGY team in Antarctica. The expedition, as it was conceived in 1956 by members of the USNC-IGY2 Glaciological Headquarters and the Arctic Institute of North America, was to be a very small, low-cost effort involving a field party of four or five men. Its objectives were simple and clearly defined. So little was then known about the area to be investigated, and even less was understood about the proper objectives for a planned study of a polar alpine glacier. At first thought, it was supposed that an alpine glacier situated in the higher latitudes should resemble morphologically temperate alpine or valley glaciers and that the ice would be something like the cold, polar ice of the ice caps of Baffin Island, Greenland, or Antarctica. This was a safe generalization as far as it went, but it was merely supposition.
The expedition planners were interested in the Romanzof Mountains which form the eastern and highest end of the long Brooks Range massif stretching entirely across northern Alaska. The Brooks Range is a natural barrier to the cold air formed in the Arctic Basin, and for this reason, had been of interest to the climatologist. The glaciologist’s concern in the Brooks Range related these climatological interests, first, to the extent to which ice once covered the western end of the mountains and, second, to the few remnants of the Pleistocene which still exist on the Romanzofs. Why and how do these few dozen glaciers, totaling little more than 100 square miles of ice, maintain themselves? Are they growing or, as appearances would indicate, wasting? Does their behavior reflect unique conditions of terrain and geographical location? Might these glaciers exist elsewhere along the North American rim of the Arctic Basin if the present day climate were slightly different? What relation might this small collection of land ice, situated only 70 miles from the Beaufort Sea, bear to the behavior of the arctic ice pack? And finally, what might be learned about the larger masses of continental ice—too large to study as a unit—by investigating the tiny mountain glaciers and correlating the data with other related studies on Baffin Island, Greenland, North American Glaciers and the Antarctic? These were some of the larger questions to which answers were sought. The specific research objectives of the McCall Glacier study which might provide answers to some of these larger questions were, first, the study of the physical characteristics of the glacier and, second, the study of the dynamic relationship between these glaciers and their environment.
In considering the establishment and maintenance of a small mountain observation station at 8000 feet elevation for 18 months, there arose many questions. People offered a host of relatively uneducated guesses about the severity of climate that should be expected, none of which could be discounted completely. The project leader, Dr. Richard C. Hubley, a meteorologist and glaciologist able to hypothesize with the little information available about the probable hazards of cold and wind that might be encountered, estimated that the wind could range as high as 200 mph during periods of strong outbreak of the arctic air blowing northwest across the range. A fairly sure guess could be made about the temperatures to be met from the records of the coastal weather stations; namely, that the coldest periods in the two months of the winter night and the yet colder weeks of early spring would occur during periods of stable calm air and that temperatures would probably not range below -35°F. except at these times. Temperatures in the summer should not average above freezing. Yearly precipitation was estimated to be around ten inches, water equivalent, with most of the moisture falling as snow in the summer. There were many old- time Alaskans, however, who insisted that it would be foolhardy to winter in the mountains. The party went to the field prepared for almost any eventuality. As might have been expected, the anticipated difficulties of living in this mountain region never materialized or, at worst, proved to be slight. Many problems concerning the conduct of the scientific study, the measurements and observational techniques, and the instrumentation were likewise anticipated and began confronting the party in the early months of the program. Careful preparation and thorough consideration of the possible difficulties reduced these impediments and provided a means of solution to new questions that arose.
In 1956 a reconnaissance party flew over the Mount Michelson area of the Romanzofs and sighted, eight miles east of this principal landmark, a slender, gently sloping valley glacier which appeared to meet our requirements: The glacier terminus was close enough to the frontal scarp of the mountains that it could be reached easily by a party on foot and might offer access by tracked vehicles; the glacier surface showed little evidence of crevassing and might permit ski landings by light planes even in the cirques; the glacier was the simplest form to deal with in a mass and energy budget study because it had no tributary glaciers and was small enough (five miles long and less than one-half mile wide) that a small party could easily reach any part of the glacier on foot.
In May 1957 components of the McCall Glacier Station were deposited by air drops from the U. S. Air Force. The permanent party of four men built the major station on the snow surface in the glacier’s highest cirque. The station consisted of a single living unit, 16 feet by 32 feet, equipped with oil heating and a diesel-powered electric generator which provided power for 24-hour, continuous recording of meteorological data. A smaller building was constructed on a lateral moraine three miles down-glacier for use by members who would spend considerable time near the glacier terminus surveying ice motion stakes. Within two weeks the station was ready for limited operation. Two members left for the lower station to begin installing and surveying the motion stakes. Snow pit studies, four-hourly weather observations, and continuous recordings of wind, radiation, and temperatures were begun at the upper station by the other members.
It should not be considered that the scientific program had two separate and unrelated parts: weather observations on the one hand and glaciological studies on the other. A common misconception about field research stations generally and glaciological research programs particularly is that they must, of necessity, include weather observations. Data from the McCall Glacier, which could be occupied less than two years, would not be valuable to climatologists who need longer term weather trends for their studies. Weather observations are often made because they relate very directly to the other research objectives of the program, not because they are of interest to the meteorologist or because the researcher enjoys recording the weather. A glaciologist who studies the heat or energy of a glacier must measure all the components of the local meteorological environment as well as the physical properties of ice. He estimates as accurately as possible, on the basis of data from ice-motion surveys and snow accumulation and melt water runoff records, the change in mass that his specimen glacier undergoes in the period of a year. This estimate indicates the glacier’s current behavior—whether it is growing, shrinking, or remaining in equilibrium. He next measures, as nearly as he can, the energy exchange that has taken place between the glacier and the atmosphere in the form of heat. He measures the energy received (radiation from sun and clouds) at the snow surface and the energy the glacier loses by radiating back toward the sky. The net energy exchange between glacier and atmosphere should reflea the net change in the glacier’s mass during the year. With information about these two processes, energy exchange and mass exchange, the glaciologist can then say something of the climatic conditions which influence the growth or wastage of the glaciers in the region of his study.
The glacial meteorologist’s task is especially difficult because he attempts in the natural environment what amounts to a laboratory experiment in which there are many variables not subject to precise measurement. He treats the specimen glacier and its local environment as a controlled system. Subject to the special conditions of terrain, instrument error, human clumsiness under harsh conditions, and generalizing from spot measurements, the glaciologist’s aim is to write the equation for energy exchange over the whole surface of the glacier.
The McCall Glacier was a particularly difficult subject, not because of the size or complexity of the system that normally baffles investigators, but because its behavior was almost so subtle as to be within the limits of error of the glaciologist’s measurements, and therefore unmeasurable as a net change. For example, snowfall was so slight—estimated as less than 15 inches of water equivalent per year—that any measurement errors would have an inordinant effect on the total and on the estimate of mass budget. Snowfall was often accompanied by gale-force winds which made the accuracy of the measurement by precipitation gauge or accumulation stake very uncertain. Returning to the upper station after a three-month absence in the winter of 1957-58, the party measured a surface lowering of two centimeters on a stake planted in the part of the cirque that should have shown the greatest accumulation; another stake at a different location indicated a three centimeter surface rise.
The glacier’s surface movement was slow. The largest average changes in stake position along a downslope direction were around four centimeters per day. The strong katabatic wind flowing down the glacier tongue caused refraction difficulties in surveying the lower stake profiles. These difficulties were sufficient to dictate against any attempt of a detailed analysis of glacier motion with data from the first year’s work.3
Summer precipitation was greater than snowfall during the late fall and winter months, and was difficult to reckon with because it sometimes fell as rain. Some of the free water in the head snows of the glacier refroze, some was lost in runoff. Because precipitation occurred in several forms throughout the year and because refreezing of water into many discontinuous ice bands and lenses took place, the observer could not rely on the usual means of estimating snow accumulation and the history of the snowpack. On temperate glaciers the yearly deposit of snow is often recognizable by the band of dirty firn formed in the summer. The McCall Glacier’s firn stratigraphy proved to be confused and inconclusive.
Even if the researcher must admit after his study that he cannot measure within the limits of his probable errors and cannot venture to answer the larger questions, he has at least uncovered a host of new problems indicated by his selected problems, and he has acquired useful information. What information, we might ask, has this study produced that the mountaineer can use as it relates, first, to the Brooks Range itself and, second, to mountain areas with similar environment?
Approaching the Range
Although many glaciers in the Romanzof Mountains provide excellent landing strips for light planes, a climbing party might wish to walk into the range. Since the highest peaks rise from the glacierized area between 143°30' to 144°30' West and 69°5' to 69°25' North, the best approaches to climbs can be made from the north slope of the range up the Hula Hula, Okpilak or Jago River drainages. The transition from the low relief of the lake-studded tundra to the mountains is abrupt. Walking less than five miles from the nearest tundra lake and gaining only 1500 feet, a party enters the McCall valley through a low pass at 3500 feet elevation. The terminus of the glacier is reached at a little less than 4500 feet by easy walking along the braided McCall Creek. The spring thaw and resulting break-up of the aufeis4 fields which are found at the termini of many glaciers in the Brooks Range presents the only difficulty in approaching a glacier terminus. In April or May, and even June, an aufets field may form a highway from one to three miles long.
Many of the glaciers of the Romanzofs are very slightly crevassed, as might be expected from their slow rate of movement, annual accumulation rate and general topography. True icefalls do not occur. There are many tiny cirque glaciers, few of which reach the larger valley glaciers as tributaries. These are only very tentative indications that the principal glaciers should not be greatly disturbed and can lead a climber to be careless. Those crevasses that occur in the McCall Glacier are the type described by Nielsen as formed by simultaneous sheer and longitudinal compression and are found along either edge of the tongue where the gradient is slight and the surface is very convex. These are straight-walled crevasses, usually from six inches to two feet wide but occasionally reaching several feet. At the entrance of the highest cirque, where there is an abrupt change in slope, transverse crevasses of one to eight feet in width are found. Small transverse crevasses were revealed in the center of the highest cirque during the project’s second summer on the glacier after a period of considerable surface v/astage. Some well-roofed crevasses, high in the accumulation area, partially fill with melt water and become festooned with icicles. It is fair to say that crevasses do not constitute an obstacle to glacier travel in the Romanzofs but remain insidious hazards for those climbers who relax their usual caution.
Contrary to- what might be expected of a mountainous area at 69° North, the Romanzofs have a very comfortable — even hospitable — spring and summer weather. Figure 1 presents the average monthly temperatures at the upper station for the period of March-October. On May 19, 1958 the temperature at the station registered above 32°F. for the first time since the previous October 24. The greatest extremes in temperatures are likely in the months of May and October when the weather is apt to be most fickle.
Considering the temperature and precipitation records together, a better idea is gained of the best months for climbing in the Romanzofs. Figure 2 shows the precipitation in several months and indicates the part that fell as rain.
In both 1957 and 1958 rain fell only in June, July, and August. The party did not occupy the station during the winter months of November, December, and January, but it is reasonable to assume from the records that the average annual precipitation in the area does not exceed 15 inches. Although total rainfall is slight, a sudden occurrence can start serious rock and snow slides. A dangerous climbing hazard was caused by the 1.4 inches of rain that fell in a seven-hour period on June 22, 1958. Electrical storms were heard on only three or four days in the two summers but generated static electricity in the buildings.
Finally the records of cloud-cover and winds complete the picture of April and May as the period of best weather for the climber. Although the cold winter months are somewhat clearer, the average cloudiness in these months is only 0.5 (1.0 for an overcast sky). The highest winds were registered in these months. The longest period of gale-force winds (above 25 mph) occurred during the 13-day period in April 1958. Winds on the ridgetops rose well above the 75 mph measured at the station on three days. The average windspeeds for these two months are only slightly higher, however, than for the other spring months.
Snow and Rock Conditions
Snow conditions change from a hard windpack, in the winter and spring, which will easily support a man on foot, to heavy, water-saturated firn in the summer which will, at its worst, support neither skis nor snowshoes. On a north-flowing glacier like the McCall which has steep walls on all sides, the heaviest accumulation of drifted snow seems to be along the western side which is in the lee of the prevailing northwesterly winds. In the winter of 1956 the randkluft5 along both sides of the glacier tongue was so filled that the surface looked nearly flat. These drifts did not disappear entirely during 1957. In the next winter, however, a very small amount of drifting occurred on the glacier—so little, in fact, that it became impossible to cross from glacier to moraine at some places. Snowdrifts at the terminus were several feet deep in 1957, slight in 1958. The main part of the glacier surface from terminus to around 6700 feet elevation may have two feet of snow accumulation, at most, filling the stream channels and bridging crevasses. Above this height small scale drifts and sastrugi are found. In the hollows of drifts the crust may be eroded very thin. Under the crust will be found a layer of hoarfrost that formed from the moistureladen last snow of the summer season. The presence of this weak layer is noticed when a large area subsides at once producing an ominous rumble.
By June temperatures have become high enough and snowfall sufficiently heavy to make travel by skis and snowshoes much easier than walking. Snow soon disappears from all of the glacier surface to the entrances of the cirques. By late summer the firn line, the altitude below which none of the firn of previous years is found, is as high as 7500 feet in the upper cirque.
The McCall Glacier is surrounded by six sentinel peaks which are part of a large granite mass several hundred square miles in area. The rock is subjected to extreme weathering by frost action. South and east-facing slopes are covered by a very unstable mantle of talus. Few clean rock faces are found anywhere in the range. Consequently, climbing routes are limited to aretes, ridges and snow or ice slopes. Even the snow slopes, because they are small and contained by gulleys, subject the climber to rockfall danger. A frightening rock avalanche containing car-size fragments was triggered in July 1958 by a prolonged fall of mixed rain and snow. Small rock slides fell at a several-minute frequency during mid-summer.
Sleep Snow and Ice Slopes
The steeper snow-covered slopes and couloirs of the McCall valley walls present a distinct avalanche hazard under certain conditions. At any time after the winter hoarfrost layer has formed beneath a wind-compacted slab, a steep slope may be considered seriously unstable. The climber must contend with wind slab over polished ice or fragile hoarfrost until the winter snow begins rapid deterioration in June. Couloirs and gulleys offer climbing routes until July unless—as happened in 1958—a few heavy rain showers remove the steeper snowpack. Numerous wet snow avalanches swept the western walls of the valley in the early summer. The steep ice of the McCall area was both the clear, blue melt-water sort and a whiter, less dense material referred to as "firn ice.” Both forms of ice become very rotten in summer on all but sheltered east-facing slopes.
At the present time the analysis of data is being done at McGill University under the direction of Dr. Svenn Orvig. The McCall Glacier Station, unoccupied since August 1958, stands intact. The emphasis of future glaciological research in the area of the McCall Glacier will depend in great part on the final results of this study and the new problems it develops.
1 Project leader of the McCall Glacier Project was Richard C. Hubley, who contributed on several occasions to the American Alpine Journal Scientific Notes. Dr. Hubley regrettably died in 1957 at the McCall Glacier Station after successfully initiating the research program.
2 U. S. National Committee for the International Geophysical Year, National Academy of Sciences.
3"Surface Motion Studies on the McCall Glacier, June to October 1957,” John E. Sater, pp. XII-6, IGY Glaciological Report Series Number 1, American Geographical Society.
4A field of clear ice produced by groundwater percolating to the surface and freezing.
5A gap between a glacier’s edge and lateral moraine, often deep and overhung with ice, found usually on shrinking glaciers.