On Tuesday, Cyclone Gabrielle triggered widespread flooding, landslides, and enormous ocean surges, prompting evacuations and trapping people on rooftops for the third time in New Zealand’s history.

Thousands of passengers were left stranded by cancelled flights, and hundreds of thousands continued to be without electricity.

At a news conference on Tuesday, Prime Minister Chris Hipkins declared that “the severity and the breadth of the destruction that we are experiencing has not been experienced in a generation.”

Australia and Britain had pledged support, he added.

At 6 p.m. (0500 GMT) Gabrielle had moved southeast of Auckland, near the east coast of the country’s North Island, and was expected to continue moving southeast, roughly parallel to the coast. Weather warnings remained in place for much of the east coast of the North Island and upper South Island.

About 225,000 people were left without electricity, while dozens of supermarkets closed, with Hipkins urging New Zealanders not to panic-buy supplies.

Architect Lars von Minden, 50, lives in Muriwai, a beach town on the coast west of Auckland.

“I’ve seldom seen anything like it,” he told Reuters by phone. “There are three or four areas where there are just these massive slips, some of them 300 metres (1,000 feet) across, that have come down, taking out houses and roads and everything.”

Kieran McAnulty, minister of emergency management, said that while New Zealand was now through the worst of the storm, more rain and high winds were expected.

The country was suffering from extensive flooding, landslides and damage to roads and infrastructure, he added.

Transmission companies around the country reported damage to substations and power networks.