Nearly 11,000 homes and businesses in Ontario's Niagara region were still without electricity Sunday morning, three days after a snowstorm toppled power lines.

Crews from as far away as Cornwall in eastern Ontario are working to get the electricity back on in Fort Erie, where a state of emergency remains in effect.

Mayor Wayne Redekop said the bulk of customers with Canadian Niagara Power Company Ltd. should have service by the end of Monday.

"We're coping fairly well under the circumstances, but it's starting to get a bit more difficult now because it's the third day without power, and people can't heat their homes."

Redekop said temperatures are hovering around two to three degrees, while "it's 12 degrees or so" inside most homes.

The town has been operating shelters for the past two nights, but the mayor said "human nature being what it is, people want to stay in their homes."

Melting snow has flooded some streets and several basements.

Across the border in Buffalo, N.Y., the storm is being blamed for three deaths after the city was hit with nearly a metre of snow.

About 325,000 homes were still without power in western New York state on Sunday. Public schools in the region will be closed on Monday.