"What we are witnessing is the power and unpredictability of nature," the BBC quotes Jane Francis of the British Antarctic Survey as saying. For the second Antarctic winter in a row, the Halley VI research station will be closed as two giant cracks continue to spread across the 500-foot-thick Brunt ice shelf.

In a press release, BAS calls it a "complex and unpredictable glaciological situation." The first crack started moving north in 2012 after 30 years of dormancy and has sped up in the last half a year, the Guardian reports.

The second, the "Halloween crack," has been moving east since appearing in October 2016 and is now more than 30 miles long. The European Spacey Agency has a map of both cracks and the location of Halley VI created from satellite images.

Halley VI will be closed between March and November 2018. Francis says it would be difficult to rescue the station's 14 staffers should the ice shelf break apart during winter's permanent darkness and frozen seas.

"The safety of our staff is our priority in these circumstances," she says. In the meantime, staffers arriving for the summer season this week plan to install automated experiments that can run on a generator unsupervised during the winter.

But that's easier said than done. "For it to keep running at -50C with nobody around to chip the ice off it or keep the snow away from it will be a significant challenge," David Vaughn at BAS tells the BBC.

The first Halley station was opened in 1956; the station collects data on climate, the ozone, and space weather. (After 106 years in Antarctica, fruitcake still looks "like new.")

This article originally appeared on Newser: Fear for Antarctic Researchers' Safety as Ice Cracks Grow