Cracks in the Ice

Antarctica is the last frontier on Planet Earth. It contains 5.4 million square miles of ice, two to three miles thick. And it’s riddled with cracks called crevasses.

One of the most hazardous places on the continent is the Shear Zone, where the Texas-sized Ross Ice Shelf meets the much smaller McMurdo Ice Shelf. These huge floating slabs of ice are constantly moving. And strong winds blow snow over the cracks, creating ice bridges that mask the danger below.

A crevasse is a crack in the polar ice, often bridged over with snow.

Since 2005, the South Pole Traverse (SPoT) has departed McMurdo Station twice every austral summer (Dec-Feb) to deliver food and supplies to the Amundsen-Scott South Pole Station. And their route goes directly through ... you guessed it ... the Shear Zone. The initial proof-of-concept route took three years to establish using Ground Penetrating Radar, dynamite, Cat bulldozers, and a team of brave souls. Every year since, SPoT teams are led by a similar GPR machine to detect any new cracks that have developed. And with roughly 10 miles of drift each year, that means plenty.

The Shear Zone is a treacherous minefield of shifting cracks

and crevasses, hidden from view.

To date, the largest crevasse recorded on the Ross Ice Shelf measured 350 feet wide and 500 feet deep. A few machines have gotten stuck in its deep crevasses, and sadly, some lives have been lost. But strides in technology and safety practices continue to allow scientists and others to navigate the Shear Zone safely. Still ... only the brave, the hardy, and the very curious make the journey.