DUBLIN — Ireland dived into a cleanup effort on Tuesday after one of the most powerful storms ever recorded in the northeastern Atlantic tore across the island, killing at least three people and leaving a trail of destruction.

Officials said hundreds of thousands of people in the country remained without power on Tuesday, after the remnants of Hurricane Ophelia tore roofs off buildings in Ireland’s largest cities, Dublin and Cork, and pushed ocean water over sea walls on its west coast.

The national utility the Electricity Supply Board warned that it could take up to 10 days to restore power to all 245,000 homes and businesses that were without electricity, which represented 12 percent of the network.

Electrical outages also meant that some water treatment plants could no longer operate. “Cobh and Youghal have run out of water,” the Government News Service quoted the utility Irish Water as saying on Tuesday, referring to towns in County Cork. “A number of water treatment plants have lost power. We’re working to restore.”