As giant ice cracks spread around it, an Antarctic research station is forced to close for winter

The Halley VI Research Station in Antarctica, positioned on a floating ice shelf jutting into the Weddell Sea, will shut down between March and November this year, according to the British Antarctic Survey .

Several lengthening cracks in the ice near the research station have raised the possibility that a large block of ice could break off from the shelf in the coming months — and out of concern for the safety of the scientists living there, the agency has decided to remove the research team before the Antarctic winter begins.

Currently, there are a total of 88 people at the station, 16 of whom were scheduled to spend the winter there.

"We want to do the right thing for our people," said Tim Stockings, the British Antarctic Survey's director of operations, in a statement. "Bringing them home for winter is a prudent precaution given the changes that our glaciologists have seen in the ice shelf in recent months. Our goal is to winterize the station and leave it ready for re-occupation as soon as possible after the Antarctic winter."

The Halley Research Station is a movable research facility currently located on the Brunt Ice Shelf, which juts out from Antarctica's Caird coast into the Weddell Sea. Research from Halley is what first led to the discovery of the atmosphere's ozone hole in 1985, although it's used for all kinds of scientific purposes, including the monitoring of climate change and sea-level rise. It's one of 30 stations participating in the World Meteorological Organization's Global Atmosphere Watch program, which monitors the chemical composition of the earth's atmosphere and helps keep track of greenhouse gas concentrations and air pollution.

The Brunt Ice Shelf currently "flows," or discharges ice into the sea, at a rate of about 0.25 miles per year, according to the British Antarctic Survey. Sometimes, cracks form in the ice and cause large icebergs to break off as well, although the timing of these events tends to be a bit unpredictable.

In 2012, a previously dormant crack in the ice shelf began to show signs of growing again, and since then it's lengthened at a rate of about a mile a year — the tip of the crack is now positioned just 6 kilometers, or 3.7 miles, from the research station. This past October a second crack appeared in the ice shelf, a few miles further from the research station, and has also continued to grow.

In recent years, the Antarctic ice sheet has attracted growing attention over the rapid melting and increasing instability certain areas are experiencing as a result of global climate change, especially in West Antarctica. However, certain glaciers even in East Antarctica, where the Halley Research Station is located — typically considered the more stable part of the ice shelf — have become increasingly vulnerable in the past few years. Even so, scientists with the British Antarctic Survey have previously noted that the cracks on the Brunt ice shelf are likely natural events.

Even so, these new conditions have raised concerns among scientists about the stability of the ice. The British Antarctic Survey is already in the process of relocating the research station to a new site further inland, about 14 miles from its current location. That process is expected to be completed by early March.

In the meantime, using a combination of field measurements, satellite data and computer models, researchers have been trying to figure out the likelihood that a large chunk of ice will break off — and how that could affect the remaining ice shelf.

For now, there are no immediate concerns about the staff's safety, according to the agency. Because Antarctica is located at the South Pole, it receives near constant sunlight during the summer and darkness in the winter. During the summer months, it's relatively easy to launch a quick retrieval of the research staff should the ice shelf begin to fracture. But the agency notes that access to the research station by either ship or aircraft is made much more difficult by the constant darkness during the winter.

Removing the staff for the winter is a precaution, now that conditions on the ice shelf are looking more precarious. All personnel are expected to be removed from the area as soon as the relocation process is complete and the station has been prepared for the winter.

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Chelsea Harvey is a freelance journalist covering science. She specializes in environmental health and policy.