Photo text: Wedgemount Glacier in 1992, the year after the ice first receded back from the lake. Photo: Bob Brett.
Barometers in the mountains
Unfortunately government funding for monitoring Whistler’s glaciers is receding faster than the glaciers themselves
By Karl Ricker
What are our glacier’s doing? In short, since the turn of the 20th century glaciers of the Whistler-Pemberton region have shrunk, both in length and volume.
World-wide this is the overall picture which has taken place after the resurgence of glacier growth which began during the mid-centuries of the last millennium. However, this phenomenon is not new. Glaciers also expanded, world-wide, between 2,000 and about 3,000 years ago, only to succumb to centuries of shrinkage. Beforehand, there was widespread glacier growth roughly 4,000 to 5,000 years ago, after a prolonged warm and dry period, termed the Hypsithermal Interval, which began roughly 7,500-8,000 years ago. At this time glaciers left over from the last ice age (11,000 to 30,000 years ago) all but disappeared. There was probably relatively little ice cover in Garibaldi Park. In southwestern B.C., there is ample evidence of tree lines that were several hundred metres above today’s tree line.
Recession of glaciers on the Mt. Garibaldi massif, for example, have uncovered tree stumps which were part of more extensive high altitude forest 5,500 to 6,000 years ago. Sea levels were higher than at present during the Hypsithermal because of the melting away of landfast ice.
So how do these relatively recent historical events on natural climate change relate to the present controversy of man-induced climate change? Certainly the glaciers of our region have a long ways yet to shrink before an equivalent to the Hypsithermal Interval is reached. The question would seem to be: is mankind accelerating the rate of reaching such an event, which would still happen even if mankind was still in the stone age?
Studies on the regimen of local glaciers are spotty. The first to pinpoint the position of a glacier snout was the botanist J. Davidson, whose explorations in the Garibaldi Park region, prior to World War 1 noted that the Sphinx Glacier terminated on the edge of Garibaldi Lake. The eminent coast mountaineer, Dr. Neal Carter, then began measurements on a few glaciers in the Garibaldi Lake region, while in the process of constructing his own topographic map of the area, which was completed in about 1926. His measurements on the recessions of the Sphinx, Sentinel and possibly the Helm Glacier were submitted to the Dominion Water and Power Bureau which took an interest in glacier studies because of their relationship to water discharge in the calculation of the power generation potential in the Cheakamus watershed. Ice melt was found to contribute 5-12 per cent of the total discharge, the glaciers acting as a natural reservoir.
W. Taylor resumed measurements in the depression years after the engineers of the Water and Power Bureau dismantled their operations. He reported his observations in the Canadian Alpine Journal. The Alpine Club have a constituted mandate to monitor the regimen of Canada’s glaciers.
World War II intervened, however, and the monitoring of any glaciers in southwestern B.C. again fell to the wayside. After the war, a bright Ph.D. student, Dr. W.H. Mathews, began detailed geological and glaciological investigations in the Garibaldi Lake and Diamond Head area. Utililizing the Garibaldi Park map, which was constructed in 1927-1928 by meticulous photogrammetric survey work, he not only had a ready-made baseline to measure systematic retreat of many glaciers in the park, but also the contour lines on the glacier surface to provide a gauge to calculate the volumetric losses of ice over the 20-year span.
On Helm Glacier, the ice shrinkage (thickness) had decreased by 45-60 metres over the entire surface, except under the headwall of Gentian Peak, where it thinned by only 10-15 metres. Fresh trim lines which showed the maximum extent of the ice (roughly 1860 A.D.) were used to estimate the recent historical shrinkage, which amounted to thickness losses of about 70-105 metres, except at the headwall where it was again reduced. This rapidity of shrinkage continues unabated today as shown by monitoring work now carried out by the National Hydrology Research Institute (NHRI), which began monitoring glaciological work in the mid-1960s as part of the International Hydrological Decade.
The NHRI work initially focussed on the Sentinel Glacier, measuring the fluctuation in glacier regimen by using a mass balance technique, rather than the simpler and less exacting methods of volumetric change or the simplest measurement of pinpointing terminus position.
The mass balance method measures the volume and density of snow added to the glacier over the winter and the volume and density of snow and ice lost over the summer to arrive at a sum of net addition or net loss of water equivalent moisture for the year.
Up to 1990 Sentinel Glacier had several years of net gain, whereas Place Glacier, located on the leeward side of the Coast Mountains above Gates Lake, almost always registered net losses.
Later, the NHRI began the mass balance monitoring of other glaciers in the Coast Mountains, including a return to the examination of an ever-diminishing Helm Glacier. However, federal cutbacks soon eroded the expansion of such activities. As well, the measurements on the Sentinel Glacier were found to have a fundamental problem of continued loss of volume, despite positive mass balance reading. The two dilemmas combined to yield staff reductions, with the moth-balling of the glaciological division at the institute and a stop on all field work on the Sentinel by any government agency. Only Helm Glacier receives a token visit and the work appears sputtering at best.
Closer to home
At Whistler the glaciological work has been done by volunteers. It began in 1973 after the writer had noted the sudden emergence of a large lake in the Wedgemount Creek basin on a visit to Wedge Mountain in 1965. The 1928 Garibaldi Park topographic map survey had shown only a small lake fronting the toe of a rather elongated glacier, descending from the summits of Wedge and Weart Mountains. But in 1965 the lake was much larger, strewn with icebergs, and it appeared to be supporting a floating ice tongue.
How fast was it breaking up? In 1973, Bill Tupper of BCIT and I finally designed a program to study the relatively unusual phenomena for this part of the world. The weather that year was not co-operating with the technique chosen, photogrammetry, and not until 1975 did it give us a break to set up all the survey control which had to be seen in rigorously positioned photos to allow precise measurements to be made.
BCIT’s Survey Department was the kind sponsor of this project. The department used it as a training ground for students and annually in September, under the guidance of Tupper, the glacier was routinely visited and surveyed for various studies. The results were then reported in the Canadian Alpine Journal as well as with the World Glacier Monitoring Service in Zürich.
Studies focussed on: the velocity of the glacier, its change in volume and total thickness, the recession of its snout out of the lake, sounding of bathymetry of the lake (60 metres at its deepest), and the age dating of its moraines left in the wake of the recession which began at the turn of the 20th Century.
In 1986, after 10 years of intense study, the investigation became another victim of the demise of Canadian institutional support for glaciological work. Furthermore, the Alpine Club of Canada had decided that glaciological reports would no longer be part of their journal. Then the project leader, Tupper, began to develop medical problems, which by 1988 halted measurement.
BCIT slowly withdrew its support for the project as the glacier withdrew from the basin of the lake by 1991. Since then, missions to the glacier, usually on the third weekend of September, have resorted to fewer studies and measurements, carried out by the writer, transferring the data to Tupper, who in his retirement years is carrying on with the volumetric calculations.
Now that the glacier has recessed out of the lake, we have been able to set up baselines, in 1992 and 1996, on the ever-expanding outwash delta, where two sets of direct taped measurement on the position of the glacier terminus can be made without resorting to laboratory analyses of photographs.
While we are way behind on the calculations on the volumetric losses, there is other data to show the ever-diminishing status of Wedgemount Glacier. Using the photos taken by the 1928 topo-survey of the park as a baseline for monitoring all changes, this is what has happened.
From 1928 to 1975 (our first detailed work), the glacier receded 987 metres, or 20.6 metres per year, but the glacier still covered about 25 per cent of the lake basin. From 1976 to 1990 (the last year of glacier terminus sitting in the lake) the rate of recession was significantly reduce, while maritime-situated glaciers located elsewhere in the world, as well as locally, were expanding.
The glacier retracted 82.5 metres, or 5.7 metres per year, but in fact did register a minor advance in 1981 and a "standstill" in 1983. However, the world climate patterns have since shifted to warmer temperatures, or perhaps locally to less moisture delivery.
In the 1990s, continual retraction has put a 108 metre long wasteland of rubble and delta between lake margin and the glacier snout as of September 23, 2000, or roughly a withdrawal rate of 10.8 metres per year. The most brutal loss in this time span was the El Niño year of 1998, registering 20.3 metres of loss, whereas the La Niña year of 1999 saw it reduced to 5.6 metres. As for this past year, a weaker La Niña event, the recession was 10 metres.
Overlord Glacier is a much different story, however. Although it has the same orientation as Wedgemount, the elevations are lower in both the upper accumulation zone and at its terminus, which at one time descended deeply into the forests of Fitzsimmons Valley. Overlord Glacier lies one ridge system nearer to maritime weather systems than does Wedgemount.
Investigations on Overlord began in 1986 by accident. While traversing the moraine crest with my young children, we noticed that the terminus of the glacier appeared to be down valley of what was shown on the topographic map in my pocket. A crude baseline was established on the spot by lining up the snout with Tremor Mountain and placing a cairn on the moraine. Returning to Russet Lake shelter in the late afternoon, the cairn and Tremor summit were lined up with an air photo-conspicuous feature at the lake, which turned out to be the outhouse!
Detailed laboratory work with sets of air photos over the winter, again using the 1928 park topo-survey photos as the baseline, revealed a surprising story. Overlord Glacier had undergone tremendous recession between 1928 and 1951 (715 metres, or 31 metres per year), but in the time span of 1951 to 1986 it had resurged down valley by 175 metres (or 5 metres per year). Since 1986, the glacier snout has been oscillating; some losses countered by minor gains — although there are two 2-year periods of significant retreat which account for much of the 103.3 metres of total recession since erection of the baseline in 1986 (or 7.4 metres per year).
In the El Niño year of 1998, it lost only 12.5 metres in position; the La Niña year of 1999 saw a gain of 0.2 to 2.2 metres. This past year posted an average loss of 2.8 metres. In recent years this glacier has developed two termini on its southern arm which compounds the measurement picture. To date the higher northern arm of the glacier is not actively monitored because it has remained back of the position of the main arm that descends into Fitzsimmons Valley.
So what do these relatively crude measurements tell us about our local glaciers, and is there any significance in the results that are important to the welfare of Whistlerites?
Glaciers are natural reservoirs of water storage, with a solar-controlled discharge being more or less evenly distributed over a dry summer when other creek systems are drying up. Almost all of Whistler’s late-summer water supplies are derived from glacier melt. If the glaciers continue to recede in areal dimensions, as was the case in the Hypsithermal Interval some 5,000 to 8,000 years ago, Whistlerites would likely have to tap the Cheakamus River directly in order to secure a stable water supply. Water consumption in Whistler is growing exponentially at present.
There are other considerations: shrinking glaciers afford less summer skiing opportunities, and Wedgemount and Overlord glaciers, which serve as a barometer, indicate that Horstman Glacier is under a natural siege of reduction, perhaps exacerbated by the way it is currently managed both in the winter and in the summer. Pushing snow downslope on this glacier with a snowcat is a recipe to reducing the driving forces which maintain ice flow, and hence loss of a glacier. Snowcats carrying rock and grit onto the glaciers in summer will accelerate the melting rate. And certainly the digging out of halfpipes anywhere on the glacier itself cannot be of benefit to its overall regimen.
And there are yet other indirect considerations. It is well known that glaciers are great cloud catchers, the snow/ice atmospheric interaction induces moisture-laden clouds to develop and hang around for hours — even days — after the storm centres have passed through. Hence, local snowfalls are prolonged to benefit our ski season and visitor counts. If the glaciers disappear, the ski seasons are likely to be shorter, and with less snow cover to hide those cliffy terracettes on Spanky’s Ladder!
So it’s in everyone’s interest to have a monitoring program on several of our glaciers. Unfortunately, the federal government cannot see that vision. Some local, environmentally aware individuals are catching on. Darren Clarke of Canadian Snowmobile and ATV Adventures jumped at the chance to help us out with the Overlord survey by giving us a lift to the Singing Pass trailhead.
As of 1986, our results are now published in the biennial journal of the BC Mountaineering Club, which took over after the Alpine Club of Canada also decided the local glaciers weren’t worthy of monitoring.