The cyclone killed 21 people and displaced more than 60,000 after it slammed into the Indian Ocean island late on Saturday, knocking down houses and electricity lines along the southeastern coastline until it moved away late on Sunday.
It also destroyed crops of rice, fruits and vegetables that were close to being harvested, worsening a food shortage in an area that was already struggling with the consequences of a severe drought, the United Nations' food aid agency said.
In Mananjary, one of the worst affected towns, many houses had been completely flattened, while others still had walls standing but their roofs were missing. Debris and uprooted palm trees lying on their sides were everywhere.
"My house started to crack and we had to leave, all of a sudden it collapsed," said resident Sezie Kajy, who was picking up clothes from her ruined home on Monday.
She said she and other local people went to a school that had been designated as an evacuation centre, but the building's roof was blown off, so they were stuck in the open.
"We were in a bad situation, all the houses were destroyed. Water from the river and water from the sea rose, all the houses collapsed, we were really scared."
The state disaster relief agency said more than 14,000 households, or more than 70,000 people in total, had their homes damaged or destroyed.
Of those, about 62,000 were in shelters, while another 8000 were either in the open or staying with relatives.
With a population of nearly 30 million, Madagascar had already been dealing with the aftermath of Cyclone Ana, which killed 55 people and displaced 130,000 just two weeks earlier.
Cyclone Batsirai struck a different part of the island, further south, where the population is facing a precarious situation in terms of food supplies because of a severe drought.
"The impact was severe and harsh and we are still counting casualties," said Pasqualina Di Sirio, country director for the United Nations' World Food Program in Madagascar.
She said the destruction of rice crops so close to harvesting had made a bad situation worse and would be felt for six months. Fruit and vegetable patches had also been destroyed.
Emergency rescuers were struggling to reach the worst affected areas because 12 roads and 14 bridges were impassable, while rising river levels were threatening to displace more people, officials said.
The state disaster relief agency said more than 200 schools were partially or fully destroyed, leaving more than 10,000 children unable to attend lessons.
President Andry Rajoelina flew to Mananjary, normally about 500 kilometres by road southeast of Antananarivo. Land routes to Mananjary were cut off due to flooding.
Rajoelina said on Facebook he went to see for himself what was needed in terms of aid.
