Dorian, which briefly reached a Category 2 hurricane Saturday afternoon but was quickly downgraded, made landfall over Nova Scotia on Saturday evening as a post-tropical cyclone, with maximum-sustained winds of 160 kilometers per hour (100 mph), weather officials said.
Nova Scotia Power Inc. told the Associated Press that 300,000 customers in Halifax, which has a population of 400,000, were without power late Saturday.
Earlier in the day, as the outer bands of the hurricane approached Canada's eastern shore, Nova Scotia suffered storm surge, coastal flooding and heavy rain. High winds were blamed for sending a crane crashing atop a building in downtown Halifax in the afternoon.
The storm was forecast to pass over Newfoundland and Labrador on Sunday.
Before reaching Canada, however, Dorian moved over extreme southeastern Massachusetts and Maine in the U.S.
On Friday, Dorian made landfall over Cape Hatteras, North Carolina, after weakening into a Category 1 storm. It generated tornadoes, severe storm surges and flooding in coastal areas in North and South Carolina.
After landfall, Dorian began moving out into the Atlantic Ocean and continued its trek up the U.S. Eastern Seaboard, the National Hurricane Center said in Miami.
North Carolina Governor Roy Cooper said there was "significant concern about hundreds of people trapped on Ocracoke Island" in the Outer Banks region.
Steve Harris, who has been on Ocracoke for most of the last 19 years, said, "We went from almost no water to 4 to 6 feet in a matter of minutes."
Before making landfall in the U.S., Dorian devastated the Bahamas, where thousands of people have begun the long, painful struggle to rebuild their lives following the onslaught of what was then an extremely powerful Category 5 storm.
The death toll in the Bahamas was 43 but was expected to rise significantly. International search-and-rescue teams were looking for survivors.
The United States and other nations ramped up efforts to assist residents in the Bahamas. Six days after the hurricane hit the islands, an estimated 70,000 people were in need of immediate humanitarian relief, and Bahamian officials said hundreds if not thousands of people were still missing.
The U.S. Coast Guard was working with the National Emergency Management Agency in the Bahamas and has rescued 295 people since Dorian hit, according to the U.S. Embassy in Nassau.
British forces aboard the RFA Mounts Bay, which has a system to turn seawater into drinking water, were distributing clean water to Bahamas residents as well as hygiene kits and blankets.
The U.N. World Food Program airlifted ready-to-eat meals, along with generators and satellite equipment, while the U.N. International Office on Migration said it was providing tarps to replace roofs stripped by the hurricane.
An array of U.S. companies also joined the effort to provide relief to the Bahamas.