Ice Palaces

Spectacular pressure ridges, glacial crevasses, and ice caves in Antarctica.

Jynne Dilling Martin
The author, Jynne Dilling Martin, in Antarctica.

Photo courtesy of Jynne Dilling Martin

One indelible image from the polar exploration classic The Worst Journey in the World comes when the explorers from the Robert Falcon Scott expedition are attempting to cross an Antarctic glacier riddled with treacherous crevasses, and they toss an empty oil can down a crevasse to see how deep it goes. Apsley Cherry-Garrard describes the terrifying noise of the can just falling and falling, seemingly into infinity, as they crouch at the edge in their reindeer skin mittens, peering down. I’ve been thinking lately about the early-20th-century miscellanea that got dumped or fell into those crevasses—that oil can, tents, horses, sled dogs, and the many men who died trying to get across the continent—and how it’s all been slowly enfolded within thousands of feet of ice. Glaciologists estimate it will be 60,000 years before the mouth of the enormous Beardmore glacier spits out those bones.

The glacier, ice, and snow formations of Antarctica are some of the most spectacular natural wonders on our planet. Even the best photos fail to convey their colossal scale, ever-changing shapes, and the prismatic rainbow effects created by sunlight on all the crystals. One especially spectacular formation called a “pressure ridge” results from Antarctica’s massive collisions of fresh and salt water: Enormous glaciers and icebergs composed of fresh water intersect with a bib of salty sea ice rimming the entire continent. This mismatch of salt water and fresh water, along with geological forces moving in total opposition—the glacier sliding slowly into the ocean, and the tides propelling the sea ice back against the continent—squeeze the two frozen surfaces together. Along these pressure lines, the ice buckles up, easily spiking as high as 20 to 30 feet into the air, creating a wildly zigzagging ridge that runs for miles.

An experienced guide led several Todgham Lab scientists and me on a tour of pressure ridges near Scott Base; although the ice on either side of the ridge is solid, the stress line itself can be precariously fragile, with slushy holes that open directly onto the ocean water below. Weddell seals take advantage of these openings to pop on and off the surface, but we humans preferred to remain both dry and alive, so we used ice picks to test stability and thickness at every step. 

Pressure Ridges
Pressure ridges on Ross Island, Antarctica.

Photo courtesy Tas50 via Wikimedia Commons

Antarctica contains 90 percent of the world’s glacier ice, approximately 6 million cubic miles; the glaciers are riddled with cracks that could easily engulf the Statue of Liberty. Though terrifyingly deep, some crevasses can be just a few inches or a few feet wide at the top, and loosely blown snow often covers and clogs their openings; many a polar explorer, many a sled dog team, and even some contemporary scientists have stepped onto what seemed firm snowy ground only to plunge hundreds of feet down. The lucky, or the well-tethered, survive; others have fallen so deep they could not be saved. 

For the past five years, NASA has been running a remarkable program called Operation IceBridge, in which a specially-equipped plane flies methodically back and forth over the continent making video of these spectacular glacial surfaces, as well as using radar to measure ice thickness and a laser altimeter to map the sub-glacial bedrock deep below. Together this data allows NASA to calculate the total volume of snow and ice, to monitor annual changes in ice thickness, and most importantly to predict how much the sea level will rise as global warming continues to escalate. The IceBridge team often works 16-hour days to maximize distances covered, which means quite a long time in tight quarters on a low flying plane. Equipped with an old-fashioned coffee pot and a microwave alongside altimeters, gravimeters, and magnetometers on the plane, members of the science team take turns eating and sleeping in between all the monitoring, videotaping, and fine-tuning of the equipment. 

Jynne Martin Antarctica
Interior of an ice cave.

Photos courtesy of Jynne Dilling Martin

Jefferson Beck, the videographer on these NASA missions, describes the experience as sometimes akin to “mowing the lawn” when the IceBridge plane spends hours flying row after row over unending flat whiteness. (Parts of Antarctica look flat from above, but the radar is still measuring critical undulations in the bedrock below.) Beck faces many challenges to getting good footage: The porthole windows on the plane are scratched, he has to run from one tiny window to another (leaping over valuable scientific equipment in the process) as the plane passes over a spectacular formation, and the turbulence from flying so low to the ground can be so ferocious that he has to press his body and camera into a piece of “standard-issue ratty old foam” which he carries everywhere with him for stability. But Beck says capturing moments of spectacular Antarctic scenery makes everything else melt away: razor-sharp ice cliffs plunging straight down into the ocean, or enormous crevasses splintering apart a glacier surface, so large that the plane’s shadow is swallowed by these yawning gaps. 

What can’t be videotaped from above are the radically beautiful interior spaces on the continent—for instance, an ice cave inside of a large iceberg that broke off the continent and began to float away but got temporarily lodged in frozen sea ice. A few weeks ago the divers Rob Robbins and Steve Rupp took a few of us to visit one such cave. The extraordinary interior, dripping with all variety of crystals, icicles, and hoarfrost formations, rivals the most beautiful palace rooms on Earth. The unusual combination of salt water and fresh water vaporizing, dripping, and refreezing within the windless interior of the ice cave allows the growth of enormous and extravagant crystal shapes. The thin snow walls allow fluctuating amounts of turquoise light to shine through, and every color of blue imaginable glows all around you. I know my friends back home might think it heresy, but I’d go see another Antarctic ice cave over a baby seal any day of the week. 

Jynne Martin Antarctica
Exterior shot of the iceberg.

Photo courtesy of Jynne Dilling Martin