This story has been updated.

Last September, the remote community of Point Lay on Alaska’s North Slope became the focus of headline news when a staggering 35,000 walruses crowded onto the shore nearby. And now, some scientists are saying a similar event could happen this summer — in fact, any time now. 

Last year’s gathering, scientists explained, had a worrying explanation. Walruses prefer to spend their time hanging out on the Arctic sea ice, which allows them a resting place in the open ocean where food is abundant. In the summer, when sea ice begins to melt, walruses typically follow the retreating ice north and migrate back south again when the ice refreezes in the fall.

But last year, sea ice in the Chukchi sea (which lies between Alaska and Russia) got down to such low levels — an increasingly common occurrence as climate change dramatically reshapes the Arctic — that tens of thousands of walruses in the area were forced to drag themselves onto the Alaskan shore in search of rest, a behavior known as “hauling out.” And this year, ice is already low enough again that it’s looking like another haul-out may be imminent.

While experts caution that it’s still too early to tell for sure whether it will happen, they’re keeping a close eye on walrus activity in the Arctic, for now. And government scientists are already preparing for the possibility.

Of particular concern is waning sea ice in the Chukchi sea’s Hanna Shoal region, a prime walrus feeding ground northwest of Barrow, AK. Historically, enough sea ice has persisted in the Hanna Shoal area throughout the summer, even while the ice melts away further south, to allow the walruses to stick around and feed throughout the warmer months. For the past eight summers, however, climate change has taken its toll on the region: Sea ice in the area has melted away to little or nothing by the end of the summer, destroying the floating haven the walruses usually rely on this time of year.

In fact, last year’s haul-out was by no means the first time it’s happened. Since 2007, walruses have hauled out every year except for 2008 and 2012, in groups of up to 20–30,000. And now, advisories from the National Weather Service in Anchorage, AK are warning that sea ice in the favored Hanna Shoal region may be gone within a matter of days.

“Sea ice floes remaining over the Hanna Shoal region are expected to be destroyed by wind and wave action along with the moderate sea surface temperatures in the region by Wednesday,” the service forecast.

If this happens, walruses in the region may be forced to move south to the Alaskan coast, just as they did last year.

“We’ve had some reports … that some walruses are coming ashore on the Russian Arctic coast,” says Margaret Williams, managing director for Arctic programs at the World Wildlife Fund. “So I think it’s highly possible that the walruses that have been in the Chukchi sea northwest of the [Alaskan] coast will be looking for a place to rest.”

Jim MacCracken, a supervisory wildlife biologist with the U.S. Fish and Wildlife Service, cautions that it’s still hard to say for sure whether a haul-out will happen. Even if satellite sensing shows that all the sea ice over the Hanna Shoal has melted, there could be enough remaining small floes, called remnant ice — too small for satellites to detect — for the walruses to stay afloat throughout the summer. This is what happened in 2012, a year when Arctic sea ice otherwise shrank to a record minimum by the end of the summer.

Still, the growing possibility of a haul-out is a concern, since the behavior can be dangerous for walruses. When they’re stuck on the shore, walruses have to swim further to get down to the shellfish they like to eat on the bottom of the ocean. “They essentially have to work harder to get their food,” says Chad Jay, a research ecologist with the U.S. Geological Survey in Alaska. “They have to swim harder, and the feeding areas are not as good.”

There’s also the possibility that so many walruses feeding in one spot could deplete the food resources in the area, says Williams. And on top of having to work harder just to eat, walruses that have gathered on the shore are prone to stampedes when they’re frightened or disturbed. If, say, a polar bear were to appear along the coastline, the walruses would flee en masse into the water, trampling calves and smaller adults and sometimes killing them. In 2007, for instance, approximately 3,000 walruses were reportedly trampled to death while hauled out on the Russian shore.

A haul-out this week would be the second-earliest such event in Alaska documented in the past decade (the earliest was the 2007 haul-out, which happened at the end of July). That’s bad for walruses because they’ll be stuck on shore for a longer amount of time — sea ice in the Arctic likely won’t start to refreeze again until October.

To help keep an eye on walrus movements in the region, the U.S. Geological Survey operates a radio-tagging program, which outfits walruses with radio collars in order to track their locations. Considering there are thousands of walruses in the Chukchi sea and only about 40 tagged animals, it’s a very rough look at what the animals are doing — but it does help give scientists an idea of where most of the animals might be hanging out at any given time.

For now, most of the tagged walruses still seem to be clustered on the remaining sea ice in the Hanna Shoal area. But recent tracking maps suggest that the walruses may have started to scatter in the last few days — possibly the result of diminishing ice in the area — and at least one has already started to make its way down the Alaskan shore. As of Wednesday afternoon, the animal appeared to be hovering just off the coast of Point Lay, the walruses’ preferred haul-out spot. 

According to MacCracken, a haul-out usually begins with a few “scout”  walruses coming to shore first and the rest following later on. Whether that will be the case this year remains to be seen. But the Fish and Wildlife Service is already preparing for the possibility of another haul-out in the Point Lay area just in case, says MacCracken. Some time next week, he says a staff member will head up to Point Lay and start talking to the community about what should happen in the case of a haul-out. The precautions are more or less the same from one year to the next: Local residents will monitor walrus movements in the area and keep the Fish and Wildlife Service apprised of what’s going on. 

They’ll also notify the local air carriers that the walruses are there and ask them to approach the village runway from the land side versus flying over the water and potentially spooking the walruses,” MacCracken says. And he adds that the Service may also contact the Federal Aviation Administration and ask them to warn other pilots not to fly over the haul-out area.

With preparations in place, the only thing left to do is watch and wait to see what the walruses do in the coming days. Even if all the ice, including remnant ice, in the Hanna Shoal region melts this week, the walruses could still hang around the area for another week or so before striking out for the shore, MacCracken says. Either way, with sea ice waning quickly, it seems as though the outcome will make itself known soon.

Chris Mooney contributed to this report.