ANTANANARIVO (AFP)

A cyclone packing violent winds has killed at least 31 people in Madagascar's second-largest city, ripping roofs off buildings, causing flooding and felling trees, the Indian Ocean island's disaster authority said Wednesday, releasing an updated toll.

Cyclone Gezani made landfall on Tuesday, slamming into the country's second city Toamasina, with winds reaching 250 kilometres per hour.

The National Office for Risk and Disaster Management (BNRGC) late on Wednesday said it had recorded 31 deaths, many after houses had collapsed.

Four people remained missing and at least 36 were seriously injured, it said, with over 250,000 people affected.

"What happened is a disaster: nearly 75 percent of the city of Toamasina was destroyed," said Madagascar's new leader, Colonel Michael Randrianirina, who had travelled to Toamasina ahead of the cyclone's landfall to support residents.

"The current situation exceeds Madagascar's capabilities alone," said Randrianirina, who seized power in October, calling on "international partners and donors" to support the island.

Drone footage shared by the BNRGC on social media showed major flooding in the east coast city of 400,000 people, about 220 kilometres northeast of the capital Antananarivo, with residents wading through water and roofs ripped off buildings.
The city appeared battered, its streets littered with trees uprooted by the force of the cyclone.

The storm also caused carnage in the Atsinanana region surrounding the city, the authority said, adding that post-disaster assessments were still under way.

"It's total chaos: 90 percent of house roofs have been blown off, entirely or in part," said the head of disaster management at the Action Against Hunger humanitarian group, Rija Randrianarisoa.

"The roads are completely inaccessible because of trees on the ground, sheet metal," he told AFP.

The cyclone's landfall was likely one of the most intense recorded in the region during the satellite era, rivalling Geralda in February 1994, it said. That storm left at least 200 dead and affected half a million more.

Commercial flights to Toamasina airport were suspended except for humanitarian and military flights, airport management told AFP.

Fifteen members of the army's civil protection unit were dispatched to assist with rescue operations, authorities announced.

The cyclone weakened after landfall but continued to sweep across the island, posing the risk of flooding despite being downgraded to a tropical storm.

It is forecast to return to cyclone status as it reaches the Mozambique Channel, according to the CMRS, and could from Friday evening strike southern Mozambique, which has already faced devastating flooding since the beginning of the year.

Cyclone season in the southwest Indian Ocean typically lasts from November to April, and sees around a dozen storms each year.