Investigating Greenland Crevasses at Raven Camp

Guest blogger Jessica Scheick reports here on a last-minute research trip to Greenland she took with her advisor, noted glaciologist Gordon Hamilton (U Maine, Climage Change Research Institute), last summer. One Friday afternoon, on what seemed like any other mid-August day in the office, my advisor stops by and asks, “What are you doing next week? Do you want to go to Greenland? We’d leave Sunday.”

Of course I did! I was just finishing up my first year of glacial dynamics research as a Ph.D. student in the School of Earth and Climate Sciences and Climate Change Institute at the University of Maine, and I’d been itching to get out to the field since I’d arrived. Sure, it was last minute, and my parents were driving up to visit me the day we were due to get home, but it was too good an opportunity to pass up.

Why the rush? Just over a month earlier record melt had occurred across Greenland’s surface, and only weeks later the sea ice extent would reach a new minimum, shattering the 2007 record. In early July, some unusual cracks had opened up across the Raven Camp skiway (about a 30 minute flight east of Kangerlussuaq, West Greenland).

The cracks pose a hazard to safe airfield operations. Understanding what caused the cracks to form and whether or not more might appear has major significance to Greenland logistics. With the field season rapidly coming to a close, time was of the essence if any investigations were to be made before winter.

Cracks – called crevasses - are common in glacial ice. However, the ones at Raven have a few surprising characteristics:

1) These cracks are located much further inland and much higher in elevation than we’d normally expect to find crevasses;

2) The cracks at Raven are closer to parallel to flow, not perpendicular (which is the normal orientation of crevasses relative to flow).

One hypothesis is that the cracks here formed due to the subsidence of surface snow layers after the drainage of a water reservoir deeper in the ice. However, without further measurements, we cannot rule out an increase in ice flow speed (the usual cause of crevasses) as the reason for the formation of the cracks.

And so a few days later I found myself in Kangerlussuaq, West Greenland, for my first taste of polar field research. Bad weather at Raven kept us from leaving Kangerlussuaq for the first couple of days, so we took some time to see Russell Glacier.

We also checked out the remains of the bridge in Kangerlussuaq that was washed out after the heavy melt in July. The weather soon cleared and we at last made it to Raven Camp.

At Raven, we spent two days setting up a strain grid, which involves installing a network  of markers, and surveying them with global positioning system (GPS) receivers.

In the spring, we will return to Raven and resurvey the markers. With this information, we can calculate flow rates and directions, and thus strain rates, which will help us determine what might be the cause of the cracks and whether or not new ones are likely to form.

Though only a short trip (less than a week), I thoroughly enjoyed my first polar fieldwork. I returned home excited about the prospect of returning to Raven in the spring and eager to continue my studies in glacial dynamics. –Jessica Scheick