CRREL scientist on mission critical Antarctic traverse

Published March 5, 2014
A traverse mountaineer climbs into the second traverse that had had the snow bridge blown off to investigate.  This crevasse was not as large as the first, measuring approximately 80 feet deep, with an approximate 10-foot wide bridge.  However, this one had another very large crevasse running perpendicular to it.

A traverse mountaineer climbs into the second traverse that had had the snow bridge blown off to investigate. This crevasse was not as large as the first, measuring approximately 80 feet deep, with an approximate 10-foot wide bridge. However, this one had another very large crevasse running perpendicular to it.

An inner tube is positioned from an arm extended from the front of a snow tractor, within the tube is an antenna that is looking down into the snow/ice layer and transmitting information to monitors.    According to CRREL Research Geophysicist Dr. Steve Arcone, “GPR is a radio method to image snow and ice stratigraphy.  The system is operated by pushing the antennas in front of a small tractor, while the operator monitors the imaged strata on a computer screen.  Crevasses are detected in advance by viewing reflections from the vertical crevasse walls.”

An inner tube is positioned from an arm extended from the front of a snow tractor, within the tube is an antenna that is looking down into the snow/ice layer and transmitting information to monitors. According to CRREL Research Geophysicist Dr. Steve Arcone, “GPR is a radio method to image snow and ice stratigraphy. The system is operated by pushing the antennas in front of a small tractor, while the operator monitors the imaged strata on a computer screen. Crevasses are detected in advance by viewing reflections from the vertical crevasse walls.”

Not many Corps employees can say that they spoke with the Chief of Engineers in the middle of the night while on a traverse in Antarctica, but Dr. Zoe Courville, a researcher at the U.S. Army Engineer Research and Development Center (ERDC) Cold Regions Research and Engineering Laboratory (CRREL), did just that.

In October 2013, the government announced a partial shutdown and as a consequence, all employee travel was put on hold.  However, CRREL Researcher Courville obtained DA-level approval, allowing her to travel to McMurdo Station, Ross Island (Antarctica) for a critical mission to ensure the safe travel of an eight-person traverse team and U.S. government personnel living and working at the Admundsen-Scott South Pole Station (SPS).

Each Austral summer, the U.S. Antarctic Program and the National Science Foundation plan and rely on two resupply missions via an approximately 995-mile overland traverse from McMurdo Station on the coast of Antarctica to the SPS (across the Ross Ice Shelf, up the Leverett Glacier, and across the Polar Plateau).  These resupply missions deliver critical fuel (a season’s supply is 200,000 gallons) and cargo to sustain the remote station. If delivery is unsuccessful, the safety and maintenance of the station would be jeopardized.

The delivery missions travel over very hazardous terrain – hazards created by extensive crevasse fields along the route.  A crevasse cannot always be seen with the human eye. What may appear to be an extension of the surrounding snow cover with radar may actually be a snow-covered crevasse (or snow bridge over a crevasse). 

This year, two large crevasses were found, en route, that requiring mitigation, investigation and filling of the void, to allow the traverse vehicles to safely continue their travel.

Courville’s expertise in crevasse detection using ground penetrating radar, a method originally developed by CRREL Research Geophysicist Dr. Steve Arcone, was critical to the safety of the eight-person team and government property during the traverse. 

Arcone’s work with GPR crevasse detection began in 1992 with practice profiles over giant slots in granite in Enfield, N.H.  In January 1993, the method was proved in Antarctica, and actually put to use in 1995, when the South Pole Overland Traverse was initially investigated.  Finally in 2002, the system was used by Arcone when he ran crevasse detection for the first crossing of the Shear Zone, located 40 kilometers (approximately 25 miles) from McMurdo Station.  Since then, Arcone, with fellow CRREL Researcher Dr. Jim Lever and in collaboration with Dartmouth College, has expanded this GRP system to the robotic program.

According to Arcone, “Ground-penetrating radar, or GPR, provides images of snow and ice stratigraphy, whether to depths of meters or several kilometers, by transmitting radiofrequency pulses from antennas riding on the ground’s surface.  For crevasse detection, the antennas are pushed about 6 meters (about 20 feet) in front of a small tractor, and the operator watches a scrolling image of snow layers on a laptop screen.  The antennas have a very wide beam width.    When a crevasse is approached, the operator is warned in two ways: 1) the snow layers start to buckle, and 2) sloping reflections appear (reflections from the crevasse walls).  As the antenna rides over the crevasse, the void shows up in the image as a long, dark vertical streak.  The tractor can be stopped almost instantly so there is no danger of equipment falling in.”

In the field, Courville woke at 1:30 a.m. to speak by satellite communications with Lt. Gen. Thomas Bostick, U.S. Army Chief of Engineers and commanding general of the USACE, who was at the time in Hanover, N.H., visiting the CRREL facility.  Although they were only connected for a short few minutes before the call was dropped, Courville took the opportunity to share with him the importance of the traverse.

Courville later received a handwritten letter from Bostick, and it reads, “It was very nice to speak with you as you were making your trip to the South Pole.  I was very impressed with the work that you and your team are doing for the Army and the nation.  I’m proud of you!  Keep up the great work.  Look forward to meeting you one day.  Thank you!  Tom Bostick.”

Had the fuel resupply mission not been executed, it would have created a life-threatening risk for SPS staff, as well as endangering SPS property.

“Thank you, thank you, thank you, for pushing hard and masterminding the coordination with others to get Zoe approved to travel to Antarctica,” said Chief Program Manager George Blaisdell with the National Science Foundation’s U.S. Antarctic Program.  “Zoe’s role is vital to keeping South Pole operational for the next 12 months.”