Down an interminable flight of stairs, leading from the elevated station to the South Pole power plant, an unheated corridor sits just below the surface of the snow. Five of us walk through this hallway until our guide stops abruptly. “There,” Jackson says, pointing to a portal at our right. The entrance is so unassuming that I have walked by it hundreds of times without seeing it.
Scot Jackson picks up his radio and dials Communications. “This is Cargo Scot. Checking out five souls. We’re going into the tunnels.”
Underneath the bustle of activity that is South Pole Station, beneath the flat expanse of snow, lie 3,071 feet of under-snow tunnels. These are utility tunnels, housing the piping that supplies us with fresh water and removes wastewater.
Scot is about to give us a tour of these subterranean tunnels. He should know them pretty well — six years ago, he built them.
“Watch your head,” Scot tells us. We duck through a wooden doorway, down a few steps, and into the belly of the tunnel. My breath clouds in front of my face; regardless of the time of year, these tunnels stay at about minus 58 degrees Fahrenheit. In the wintertime, when outside temperatures can plunge as low as minus 120 de-grees F, these tunnels provide shelter and access for system operations and maintenance.
As we walk deeper, I’m amazed to see the tunnels are entirely unlined and unsupported. They’re carved out of extremely hard subsurface snow, or firn. For the most part, the corridor maintains a rectangular cross section of 6 feet by 10 feet.
“How deep are we?”
“At shallowest, we’re 18 feet below the surface. At deepest, 45 feet,” he said.
It took three years to build these tunnels. “We needed a way to have maintenance access to the water piping, independent of outside temperature extremes, drifting snow and long winter months of darkness,” Scot said.
The piping in these tunnels brings fresh water from various wells to the station. The wells are drilled through the top layer of snow and firn into the ice below — usually about 200 feet deep. Waste heat from the station’s power generators is used to melt ice in the well, starting a “bulb” of fresh water at the well’s base that grows as it thaws. Once it reaches critical dimensions (about 100 feet wide by 400 feet deep), this liquid fresh water is pumped up through these pipes to the station. The empty well is then used as a repository for wastewater.
The two thick pipes, wastewater and freshwater, run suspended from the wall of packed snow. Scot points out landmarks as we walk, noting the slight grade under our feet — we’re slowly descending deeper into the snow. After a sharp turn in the tunnel, we venture into one of the seven side tunnels. “Walk carefully here — and look up.” This tunnel is full of stalactites of ice crystals, stretching down like intricate sculptures from the ceiling. They sparkle in the light provided by a few bare light bulbs and the beams of our flashlights.
“We used a tunnel boring machine, a prototype developed for us by the U.S. Army Corps of Engineers, to excavate many tunnel segments,” Scot tells us. “But we also did a lot of hand work with chain saws. … You can cut blocks out of the tunnel face and tap them out fairly easily.”
He points to marks on the walls and ceiling indicating manual excavation. “We worked these sections in three-person shifts. One person would work with the chain saw, cutting — that was the coldest job. A second person would be clearing the cut snow out of the way. The third person would be in our warming shack, getting ready to relieve the cutter.
“It was very cold work, down here underground.” After just 30 minutes in the tunnels, our eyelashes are caked with ice.
If you hit the wall of the tunnel with your fist, you will barely dimple the snow — the firn is that strong, and these unsupported passageways stand reliably. You can screw a long, coarse-threaded lag bolt into the ceiling, you can hang on it without breaking free.
“We ran the bulldozer over the tunnels on the surface a few times just to be sure they would hold,” Scot said.
Scot’s eyes sparkle as he describes working on the tunnels. “It was a pretty special project,” he says. “I’m glad to have been a part of it.”
We emerge from the tunnels at last and radio Comms. “We’re back on the surface,” Scot says.
The world of the tunnels disappears behind us — hidden beneath the snow.
Meg Adams, who grew up in Holden and graduated from John Bapst Memorial High School in Bangor and Vassar College in New York, shares her experiences with readers each Friday. E-mail her at firstname.lastname@example.org.