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Sixty years ago this month, in September 1954, the US Army Corps of Engineers completed its first summer of construction at Camp TUTO, Greenland. Camp TUTO was tucked against the Greenland ice sheet east of Thule Air Base. The gently sloping ice sheet adjacent to the camp, earmarked for vehicle access to the ice sheet interior, was named Thule Take-Off (or TUTO). Over the summer of 1954, some of the one hundred soldiers stationed at Camp TUTO built a gravel road up the first 1500 meters (4700 feet) of TUTO Ramp. Although that got them above the sometimes bare ice and slush of the lower elevation ice sheet melt zone, it still proved difficult to drive over the soft snow of the higher elevation ice sheet accumulation zone.

In official reports, the US Army Corps of Engineers tested “every off-road military vehicle (probably not excepting Hannibal’s elephants)” in the search for a suitable over-snow vehicle. The M29C Weasel, originally designed as an amphibious vehicle late in the Second World War, had proved disappointing in swampy terrain, but exceptionally nimble on the ice sheet. Although the Weasel was out of production even before construction started at Camp TUTO, it became a beloved backbone of US Army logistics on the Greenland ice sheet for almost two decades.

Constructing TUTO Ramp and adopting the Weasel opened up the interior of the Greenland ice sheet for a wide array of military engineering activities, including the construction of ice sheet runways and under-snow stations, as well as civilian science activities, including recovering the first “deep” ice core and wide-ranging snow and accumulation surveys. An auspicious anniversary of a ground-breaking project in applied glaciology!

(skimmed from my upcoming Cold War science project.)

The view up TUTO Ramp, from the ice margin at Camp TUTO, on to the Greenland ice sheet in 1954. (from Nate Galbreath at thule1954.com)

Modified M29C Weasels in convoy (left) on the Greenland ice sheet in 1954. (from Nate Galbreath at thule1954.com).

I have a paper in this month’s issue of the Journal of Cold Regions Engineering that examines the ice excavation required to establish and maintain an open ice pit. Excavating an open ice pit is a very non-linear applied glaciology problem, as the excavation of ice from an open ice pit enhances subsequent ice flow into the open ice pit. This is because ice velocity is very sensitive to changes in ice geometry, with third and fourth order dependencies on ice slope and thickness respectively! The paper examines scenarios based on excavating an open ice pit on the Greenland ice sheet margin that extends 1000 m into the ice sheet, with a 200 m high ice wall. That is the approximate dimension of the Isua Prospect, Greenland, which is projected to excavate about 36,000,000 tonnes of glacier ice per year.

Working with such unnatural combinations of ice slope and ice thickness compels you to reconsider fundamental principles of glacier mechanics, such as the appropriate relation between stress and strain at tremendous basal shear stresses, which are inconceivable in virtually all natural glacier settings. Despite an increasingly pressing need for a comprehensive understanding of how glaciers respond to highly transient forcings, however, most private sector glacier management projects cannot contribute meaningful observational data to advance such fundamental science due to proprietary considerations. Perhaps that can change in the future!

W. Colgan. 2014. Considering the ice excavation required to establish and maintain an open ice pit. Journal of Cold Regions Engineering. 28: 04014003. doi:10.1061/(ASCE)CR.1943-5495.0000067. Available here.

Supplementary online material (including animations): http://www.williamcolgan.net/som/CRENG113

Cross sectional ice velocities flowing into an open ice pit at excavation years 2.5 (left) and 10.0 (right) sampled from 30-year animations. Dashed black line denotes original ice surface, dash red line denotes ice pit wall. (from Colgan, 2014)