But while some in the village of Inukjuak expressed relief, others feared the orcas might not have escaped danger.
Many locals believe the water currents and ever-moving ice in the massive, frigid bay may eventually box the mammals in somewhere else.
One expert in Arctic wildlife said they have good reason to be concerned, because the thicker winter ice has yet to form on the bay. The orcas, meanwhile, were still 1,000 kilometres from where they should be at this time of year, said Pete Ewins of World Wildlife Fund Canada.
"They got stuck (in Hudson Bay) and they're unlikely to get out," said Ewins, adding that killer whales are not accustomed to ice.
"These guys are on the edge and they might not make it through."
The animals' predicament made international headlines and the stunning images of the orcas circulated via media around the world.
For at least two days, the mammals were trapped around a single, pickup-truck-sized breathing hole in the sea ice, about 30 kilometres from Inukjuak.
Locals captured images of the orcas frantically bobbing for air from the opening, which allowed only a couple of the animals to surge for oxygen at a time.
The killer whales were first spotted Tuesday and were last seen at the hole late Wednesday. On Thursday, two Inukjuak hunters reported that the waters had opened up in the area and the orcas were gone.
Some villagers were skeptical the killer whales had escaped harm, so the community hired an airplane to scan the region Thursday for signs of the pod.
Mark O'Connor of the regional marine wildlife board said the aerial search did not locate the orcas, but he noted that large swaths of ice-free water were seen in the area.
"So as far as I could tell, the emergency, for sure, is averted," said O'Connor, the board's director of wildlife management.
"Whether the whales have found a passage all the way to the Hudson Strait, we probably will never know."
Inukjuak's town manager believes the orcas escaped the ice when the winds shifted overnight and blew back into the bay. Johnny Williams said the direction change seemed to have pushed the floating ice further away from the shore, loosening its coverage on the water.
He also credited the new moon for changing the conditions.
Tommy Palliser, a local government official, said in an email Thursday that the orcas' once-inadequate breathing hole was about 500 metres wide and up to five kilometres long.
He also expressed concern about the varying conditions.
"The problem is the wind is coming in again from the sea ice," wrote Palliser, a business adviser for northern Quebec's regional government.
Locals in Inukjuak, about 1,500 kilometres north of Montreal, believe the orcas were initially pinned under a vast expanse of ice after a sudden drop in temperature caught them off guard.
Ewins said that in recent years climate change has reduced sea-ice cover in Hudson Bay, opening the door to predators like orcas to spend more time there feeding in summer.
But sometimes they don't make it out, he said.
Ewins pointed to three ways to respond to the situation: rescue operations, such as helicopter lifts and icebreaker-dug channels; destroying the orcas if they start to suffer; and allowing nature to take its course.
"These clearly are the minority of the killer-whale population that didn't quite get it right and get out in time," Ewins said.
To survive the winter in the bay, he said the killer whales would have the challenge of moving from one ice-free area to another until the floes recede from the bay in May.
Experts say sea ice is known as a natural cause of death for marine mammals like orcas.
Palliser, who saw the animals up close several times, said they appeared to have less energy late Wednesday, the last time he saw them.
Many thought time was running out for the killer whales on Wednesday, as their breathing hole seemed to have shrunk in the freezing temperatures.
Inukjuak Mayor Peter Inukpuk asked the Department of Fisheries and Oceans on Wednesday to send an icebreaker to smash the ice to free the orcas, but he said he was told the site was too far away and that the ships were unavailable.
The federal department said Thursday that two DFO scientists were headed to the village to collect information.
Villagers, nonetheless, were ready to take action. They had made plans to launch a daring rescue operation Thursday in an effort to buy more time for the gasping killer whales.
Locals had agreed to attempt to enlarge the existing breathing hole — and cut a second opening using chainsaws and drills.
Williams hopes the villagers' prayers have been answered.
"These mammals are the same thing as humans, they deserve to live like everybody else," he said. "They don't need to suffer."
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