New Zealand, Battered by Cyclone Gabrielle, Declares State of Emergency

New Zealand declared a national state of emergency for only the third time in its history on Tuesday after a potent cyclone flooded parts of the country, knocking out power to nearly a quarter million residents, stranding people on rooftops and sweeping at least one sailor out to sea.

The cyclone, Gabrielle, battered most of the North Island, the northern part of the country, which includes its most populous city, Auckland, according to the National Emergency Management Agency. Military officials said that at least 200 members of the Royal New Zealand Navy, the army and the Royal New Zealand Air Force were involved in the response.

“Cyclone Gabrielle is the most significant weather event New Zealand has seen this century,” Chris Hipkins, New Zealand’s prime minister, said at a news conference. “The severity and the breadth of the damage that we are seeing has not been experienced in a generation.”

Officials said that the cyclone had socked the North Island with heavy rain, severe winds and very large waves before moving out to sea. MetService, the national weather authority, said that wind gusts of more than 90 miles per hour had blasted many parts of the island and that a few exposed areas had reported gusts of more than 105 miles per hour.

Nearly 16 inches of rain fell in some parts of the North Island, according to MetService, and nearly eight inches fell in Auckland.

Mr. Hipkins said that while the full picture of the damage was not yet clear, “what we do know is the impact is significant and it is widespread.” Officials reported that at least one person had died, a woman whose home was crushed by a landslide in the village of Putorino.

A firefighter was missing and another firefighter was critically injured during rescue operations, the authorities said.

The cyclone cut power to about 225,000 customers on the North Island, Mr. Hipkins said, and utility companies reported that they had not seen such damage to the grid since Cyclone Bola in 1988. Mr. Hipkins said that crews were working to repair the damage, which had disrupted cellphone communications as well.

Roads throughout the North Island were flooded, he said, and travel delays were expected at airports. Officials said that heavily flooded roads had made it difficult to replenish dwindling food and water supplies in some areas.

The national state of emergency, officials said, applied to regions that had previously declared local states of emergency: Northland, Auckland, Tairawhiti, Bay of Plenty, Waikato, Hawke’s Bay and Tararua District.

New Zealand’s two previous states of emergency were declared in 2020, near the start of the Covid-19 pandemic, and in 2011 after an earthquake struck Christchurch, its second-largest city, killing 185 people.

Roger Ball, acting director of civil defense emergency management, said that the declaration would empower officials to direct resources to flooded regions and would reassure the public that “no effort will be spared.”

Military officials said they had deployed helicopters to rescue people from rooftops in Napier, a coastal city on the North Island.

The country’s navy said it had also launched a rescue operation in severe storm conditions to save a sailor who had been swept out to sea on a catamaran. The sailor, who was wearing a life jacket, was pulled from the ocean by two Navy divers on an inflatable boat, officials said.

Military officials said they had also relocated 60 to 100 people from Hastings, an inland city on the North Island, and had cleared downed trees, moved medical supplies and responded to an emergency call to evacuate residents after a river burst its banks.

The storm was expected to move away from the North Island on Wednesday, weakening along the way. Heavy rain was still expected to drench parts of central New Zealand through Thursday, MetService said.