Two hunters from Inukjuak village reported the water had opened up around the area where the cornered whales had been bobbing frantically for air.
Locals said the mammals had been trapped around a single breathing hole for at least two days.
Village leader Tommy Palliser said villagers had been planning to launch a rescue operation.
But he says the winds seemed to shift overnight, pushing the floating ice further away from shore to open up the water.
Mayor Peter Inukpuk had urged the Canadian government to send an icebreaker.
A hunter first spotted the pod of about a dozen trapped whales at the hole, which is on the eastern shore of the Hudson Bay. Inukjuak is about 1,450km north of Montreal.
Dozens of villagers made the one-hour snowmobile ride to see the unusual spectacle. They snapped photos and shot video of the whales surfacing in the opening and even thrusting themselves skyward while gasping for air.
One woman who made the journey to the gap in the ice said even a curious polar bear approached the hole amid the commotion. Siasie Kasudluak said the bear was shot by a local hunter for its meat.
The trapped orcas appeared to be in distress, but locals were ill-equipped to help out.