Tropical Cyclone Gafilo which swept through northern Madagascar at the weekend returned to the southwest of the country on Wednesday but officials said there were no immediate reports of casualties.
The northeastern town of Antalaha was almost entirely destroyed by winds of up to 225 km an hour after Gafilo first made landfall on Sunday.
Authorities on Wednesday told IRIN that 13 people were confirmed dead, but the death toll was expected to rise. The heavy downpour had left an estimated 55,000 without shelter.
"Some areas are still inaccessible, which means that we do not have a complete picture of the damage or how many people have been killed," presidential spokesman Raymond Ramandimbilahatra said.
A preliminary assessment had shown that 95 percent of buildings in Antalaha were destroyed by the storm. "This is very worrying because it is the main region for vanilla production," Ramandimbilahatra added. Vanilla is vital to the country's struggling economy and accounts for over 10 percent of its gross domestic product.
The damage was even worse in the smaller towns of Antsiranana province, where residents were still without water and electricity.
"Almost 75 percent of villages in Andapa and Ambajana have been destroyed, and in Ambilobe several hundreds of hectares of fields have been flooded. We have attempted to supply the residents in the area with tents and food supplies, but we definitely need some assistance," Ramandimbilahatra told IRIN.
Following a government appeal for international aid, France on Monday offered logistical support to transport relief supplies to affected areas.
Aid workers in the capital, Antananarivo, told IRIN the urgent needs were temporary shelter, medicines, water purification tablets, food and building materials.
The World Food Programme (WFP) has said it will make some food available, although it is already struggling as a result of insufficient funds for its current operations in drought-affected communities in the south.
In a related development, officials said rescuers were still searching for the 113 passengers aboard a ferry, who were feared dead after the vessel failed to arrive in Madagascar as scheduled on Monday, a day after Gafilo first hit the island.
The Samson had been sailing from the Comoran island of Anjouan for Madagascar's second port of Mahajanga.