After a rigorous search in the rapidly melting Siberian Arctic, researchers on the world’s biggest North Pole expedition have finally found an ice floe on which to set up camp.

Soon the scientists will cut the engine on the research vessel Polarstern and lodge their ship in ice. Trapped, the ship will spend the next 12 months floating with the floe across the central Arctic as its passengers collect crucial information about the effects of climate change in the fastest-warming part of the world.

The multination, $134 million Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) is the first major modern research project to drift across the North Pole. A rotating cast of some 300 scientists is slated to live and work aboard the Polarstern this year; by documenting an entire year of change in the north, they hope to improve models of how Arctic melting will affect weather in the rest of the world.

Organizers spent months combing through satellite imagery and historic records, weeks conducting helicopter survey flights and days crisscrossing ice on snow machines and sleds before making their selection of a floe this week.

The process was made more difficult after a summer of record warmth; by September, there were very few ice floes thick enough to support the expedition.

On Sept. 28, scientists aboard the Polarstern set foot on an oval-shaped floe about 1.5 miles in diameter. Viewed from space, the floe looked mostly dark — a signature of thin ice riddled with melt ponds.

But when researchers surveyed a bright white region in the floe’s northern edge, they found several feet of firm, highly compressed ice — an ideal surface on which to set up camp. They named this stable area “the fortress.”

“We’ve found our home for the months to come,” MOSAiC’s expedition leader, Markus Rex, a polar scientist at Germany’s Alfred Wegener Institute, said in a statement. “It may not be the perfect floe, but it’s the best one in this part of the Arctic and offers better working conditions than we could have expected after a warm Arctic summer.”

Arctic ice extents at the end of this melt season were the third-lowest on record. About 800,000 square miles more open water was exposed in the middle of September than is typical for that time of year. This meant the Polarstern and its support ship, the Fedorov, had to sail farther and search harder for a suitable ice floe.

In his blog, MOSAiC researcher Marc Oggier described the ships slicing through fragile, soupy “grease ice” until at last, on the horizon, the voyagers spotted the thin white line of the ice edge.

Now the researchers must work to swiftly set up camp. The six-month Arctic night is fast approaching; as of Friday, the sun will no longer rise above the horizon. Soon, all daylight will disappear.

The camp will resemble a small city, lit by floodlights and linked by pathways made of wooden planks to ensure that no wayward explorers accidentally walk across a colleague’s experiment. Oceanographers, geophysicists, meteorologists, biologists and a host of other researchers will collect information on every imaginable aspect of the sea, ice, sky and their inhabitants. The data will be fed into a gigantic database shared first with the hundreds of MOSAiC collaborators, then with scientists all over the world.

“The data will be the legacy of this expedition,” said Don Perovich, a Dartmouth geophysicist and one of the co-leaders for MOSAiC’s sea ice experiments.

Read more: