OTTAWA — Winds produced by the remnants of Hurricane Dorian tore roofs off buildings, downed trees, collapsed a construction crane and left hundreds of thousands of people without electricity in three provinces in Canada on Saturday.

A storm surge accompanying Dorian produced waves estimated to be 50 feet high, jeopardizing coastal villages. Online maps posted by utilities in Nova Scotia and the neighboring provinces of New Brunswick and Prince Edward Island showed that more than 450,000 locations were without electricity on early Saturday evening, the result of wires being knocked down by intense winds before the storm made landfall.

As the winds began inflicting damage in Canada, the storm was upgraded to a Category 2 by hurricane tracking services in both Canada and the United States. But by Saturday afternoon they declared that Dorian was no longer a hurricane but “a very intense post-tropical system.” That aside, Environment Canada, the country’s weather agency, reported that its offshore weather buoys were recording winds of more than 90 miles an hour and waves as high as 65 feet.

“All that’s changed is the storm’s structure,” Bob Robichaud, a meteorologist at the Canadian Hurricane Center, told reporters in Halifax, Nova Scotia. “We’re still talking about a very dangerous storm.”