Next spring, our team will be heading off to Mount Logan, climbing in the service of collaborative scientific understanding. And that’s why it was a no-brainer when Michael Schmidt, a long-time geophysicist with the Geological Survey of Canada, and team leader a 1992 RCGS-sponsored expedition that first used GPS technology to establish the mountain’s official height, asked Alison Criscitiello and myself whether we’d be willing to re-measure the height of Mount Logan. Our response was an enthusiastic “yes.”

In 1992, when Schmidt’s expedition measured Mount Logan’s snow and ice-encrusted top at 5,959 metres above sea level (+/- 3m), the Global Positioning System – a project initiated in 1973 by the U.S. Department of Defense – was still three years away from being fully operational. This meant that the 1992 team, equipped with early-generation GPS receivers, could only take their readings during a very short period of the day, when there were sufficient satellites available. Their success in doing this made their 1992 summit achievement all the more remarkable. “[It] was no ordinary ascent,” Schmidt wrote afterwards, in a Canadian Geographic exclusive titled “To the Top of Canada.” “We were combining science with climbing and our summit bid had to be timed carefully to coincide with the position of satellites that orbited far over our heads.”

IMAGE GPS antenna level with Mount Logan’s main summit in 1992 (Michael Schmidt).

 

As if climbing Mount Logan itself isn’t challenging enough. We’ll likely have it a wee bit easier in the spring of 2021 than Schmidt did in 1992 – if only in terms of the technology.

Since its early days, GPS has come a long way, especially in terms of its ease-of-use, reliability, accuracy, and data processing. High-quality receivers today pick up all the non-military signals from the much larger Global Navigation Satellite System (GNSS), an umbrella term that encompasses all global satellite positioning systems, including GPS (USA), GLONASS (Russia), Galileo (EU), BeiDou (China), and others. “These new systems,” according to Schmidt, “combined with advances in data processing and analysis techniques, provide incredible all-weather positions, including measuring the height of mountains down to just several centimetres.” Making use of so much more information, today’s receivers can also record data twenty-four-hours-a-day. All of this combined with significant improvements in both satellite measurements and modeling of where the sea level is under the mountains – that theoretical surface known as the Geoid – further reduces the uncertainty of measured elevations.

It’s exactly this type of technology that Schmidt’s colleague, Gérard Lachapelle, Professor Emeritus of geomatics engineering at the University of Calgary, is putting to good use today. Lachapelle has been combining his love for hiking with his expertise in satellite-based navigation to revise mountain heights in the Rockies. All of Lachapelle’s re-measurements can be found on the Kananaskis Trails website.

With the assistance of Schmidt and Lachapelle, and with a generous loan of two high-end GNSS receivers from the University of Calgary, we’ve been familiarizing ourselves with the instruments prior to taking them north, figuring out their ‘ins and outs’ (or would it be ‘ups or downs’?). Just before the COVID-19 pandemic made social isolation necessary this spring, we ran them up onto the roof of the Tory Building, the highest building on the University of Alberta’s North Campus – and measured its elevation. (It rises to 729 [+/- 0.2] metres above sea level, if anyone’s interested.)

An even better test of the receivers came a few days later, this time on the border of Banff and Yoho national parks, high up on the Wapta Icefield, the southern-most of the major icefields straddling the Continental Divide between Jasper and Lake Louise. The Wapta is one of the most studied icefields in all of Canada. In fact, one of its lower-altitude outlet glaciers, the Peyto Glacier, has been the focus of critical mass-balance studies for over a half-century – and, as such, serves as a key regional indicator for glacier recession. Most know the Wapta, however, as a ski-mountaineering destination, made all-the-more popular by a series of small mountain huts owned by The Alpine Club of Canada, the availability of a specialized topographic map made for climbers and skiers, and up-to-date guidebook information.

IMAGE The view northwards on the Wapta Icefield. February, 2020 (Zac Robinson).

 

As luck would have it, joining the group for our quick Wapta reccy was the guidebook author himself, the Banff-based mountain-aficionado, and recipient of the 2018 RCGS Sir Christopher Ondaatje Medal for Exploration, Chic Scott. Few know the mountaineering history of the Divide better than Scott, who, now in his seventy-fifth year, made easy work of the ski in from the Icefields Parkway (Hwy 93) to the ACC’s Bow Hut, all the while regaling us with stories from his youth, like when he and three companions – most of them teenagers – took it upon themselves to become the first to traverse the long line of icefields from Jasper to Lake Louise on skis. For Scott, a trip up to the Wapta is like visiting an old friend. “Change,” he told us, while we sat around the Bow Hut’s warm fire that evening, “is the only constant in the seemingly eternal hills.”

IMAGE Chic Scott preparing some appetizers at the ACC’s Bow Hut. February, 2020 (Zac Robinson).

 

A day later, under a cloudless sky and with little wind, we stood, with a GNSS receiver affixed to the bedrock, on top of the dome-shaped Mount Gordon, a hulk-of-a-peak that crests the icy watershed just inside the eastern boundary of Yoho National Park. The unseasonably warm February temperatures allowed us to comfortably run the instrument for half-an-hour or so – plenty of time, we’d been told, to get a really precise result. Long enough, too, to reflect on the others who had been here to measure the heights, and why it mattered to them.

IMAGE Zac sets up the GNSS receiver on Mount Gordon’s summit. February, 2020 (Jeff Kavanaugh).

 

Mount Gordon’s earliest known elevation measurement comes from the peak’s first ascensionists: an 1897 party of British and American climbers, who, along with a Swiss guide, also gave the peak its name, for the Earl of Aberdeen, John Campbell Hamilton-Gordon, Canada’s seventh Governor General. No matter that they believed they were ascending Mount Balfour, a much larger peak four kilometres to the southeast, or that on their descent one of them would end up twenty metres down a crevasse requiring a spectacular rescue. The party consisted of mountaineering’s cream-of-the-crop, and like so many late-Victorian mountaineers, they had a particular proclivity for delineating things. In their exploratory zeal for measurement – with a kit of instruments that, somehow, included a barometer, sextant, plane table, chronometer, telescope, aneroids, compasses, and cameras – they gave us a measurement for Mount Gordon: 10,600 feet, or 3,231 metres.

Turns out they weren’t too far off. One-hundred-plus years later, their well-earned estimate has come down, but only by about seventy metres. Current topographical maps put Mount Gordon’s height at 3,161 metres.

A day out from the Wapta, we emailed the information we had collected from our sunny, mountain-top visit to the Geodetic Survey Division of Natural Resources Canada, and, remarkably, within minutes, we received back a detailed breakdown of the results. The data our GNSS receiver recorded confirmed, pretty much, what the maps say – it put the top of Mount Gordon at 3,159 (+/- 1) metres above mean sea level. The slight difference is consistent with what Lachapelle and his team generally finds for elevations elsewhere in the Rockies: that is, most are now fairly accurate.

It’s an exciting proposition to take these new generation receivers to Mount Logan, and in particular to its high summit plateau, a place predominantly made up of snow and ice. Now, in an era of increasingly pronounced climate change, nearly thirty years after his RCGS team gave Mount Logan’s main summit its official height of 5,959 metres, Schmidt feels “it would not be surprising to see a difference from 1992 as a result of the variability in summit snow and ice over time.” Equally exciting is the chance to measure some of the mountain’s great sub-peaks, the heights of which have never been determined with GPS.

And then, Schmidt reminds us, slyly, there’s that other lingering ambiguity: and this one’s not so much about height, but rather the main summit’s snow depth. How deep is it? Where does the bedrock lie? And which is the official highest point anyway, the snow or the rock?

In March 1975, Gerald Holdsworth, an eminent ice-core scientist with a long relationship with the Canadian Arctic, penned an article for Canadian Geographic titled “Taking the measure of Mount Logan.” It neatly laid out what was at that point a near century-long preoccupation among surveyors and climbers to determine the exact height of the Yukon’s Saint Elias Mountains. “An element of mystery often surrounds regions of very high altitude,” wrote Holdsworth, knowingly. “Mount Logan, the highest point in Canada, is no exception.”

Here in the twenty-first century, climate change may well be giving that mystery a longer life than previously believed.

Zac R.