Only 144 Miles, Yet Worlds Apart
144 miles separates Kangerlussuaq from Raven Camp. Not far really, just 144 miles – like traveling from the southern tip of New York City up to Albany. Flying at 270 knots we can be there in about half an hour, no time at all, and yet to the casual observer they seem worlds apart.
Kanger sits nestled in the arm of Sondrestrom Fjord, where over the years Russell Glacier has found the soft belly in the rock base, wearing the surface down flat and pushing the rock flour out to sea. Currently the tip of Russell Glacier is a full 20 kms (14 mi) up the fjord. In the summer months, as research teams move through the village, glacial meltwater fills the carved channel that borders the small town.
Meltwater Rushing Behind Kangerlussuaq, Greenland
“Summer meltwater from Russell Glacier rushes around the edge of Kangerlussuaq.”
Although modest in size by our standards, Kangerlussuaq is a transportation hub for Greenland, and has a steady year-round population of ~500 residents.
Raven Camp sits high up on the Greenland Ice Sheet on a frozen bed of ice, almost 2 kms thick (~1 mi) and millions of years in the making. At almost 7,000 feet of elevation, no seasonal change will bring a rushing river or a population to match that of Kangerlussuaq, but summer research does bring an influx of summer scientists, swelling the population beyond the posted total of 2. With a handful of tents and collapsible housing structures, Raven Camp is a “summer town.”
Today we fly to Raven Camp to complete a survey grid over the ice landing strip. A year ago the camp staff detected several cracks (crevasses) in the ice running perpendicular to the airstrip. Crevasses are to be expected around the edges of an ice sheet, where the ice is faster flowing, however, at this elevation and this far inland it is more unusual. Published data for ice movement in this area shows at the base the ice is moving about 2.5 cm a day, while at the surface ice is moving closer to 7 cm a day. It is no surprise that the ice at the base moves more slowly, a result of the increased friction at the bed causing the ice to stick and slow.
Currently measuring only 10 cms across, it certainly doesn’t seem that this could cause much trouble. But if the crevasses are deep and continue to widen, they will threaten the landing strip. A team of scientists has been collecting measurements on the ground to see if these rates are changing (2013 polarfield blog1); our job is to survey the area with our instruments. The Shallow Ice Radar and the infrared camera collect the depth of the cracks and the temperature differences as the cracks move deeper into the ice. Pulling all this data together will help us understand what is happening to the ice in this area.
Our flight grid will be flown low, at 1,000 ft. above the ice surface, one third our normal survey elevation. Two East/West lines are flown perpendicular to the landing strip at 600 meters apart. Then three tie lines are flown parallel to the runway at 100 meters apart.
Once the grid is complete, we land on the airstrip, testing the seal on the pod door and collecting some camp cargo. The landing is smooth.
Temperatures today at Raven are a warm 1°C. The snow has lost some of the crispness we had experienced when we had landed in April to install a GPS on the ice. The pod is inspected. The camp looks all but abandoned, yet a snow vehicle appears with cargo that is stashed and secured for transit. While the cargo is loaded, we snap a quick IcePod team photo.
The new eight-bladed propellers on Skier 92 do their job and the take-off is smooth for our return to Kangerlussuaq, just 144 miles, 30 minutes of transit, and yet seemingly worlds apart.
1 For more on the science being collected on the ground on ice movement: http://www.polarfield.com/blog/tag/greenland-ice-cap/
For more on IcePod: http://www.ldeo.columbia.edu