Flooding and landslides caused by the passage of tropical storm Cheneso across Madagascar caused 30 deaths, left 20 people missing and affected tens of thousands across the Indian Ocean island nation, according to a provisional assessment Monday. The storm made landfall in the northeast of the island last Thursday and impacted close to 89,000 people, Madagascar's National Office for Risk and Disaster Management said. Madagascar's meteorological agency said the storm, which has now passed across the country into the Mozambique Channel, saw winds gusting up to 170 km per hour (105.63 miles per hour) and unleashed torrential rains.

Colonel Faly Aritiana, of the risk and disaster office, said there had been house collapses and landslides in which people have become trapped.

"People have been reacting generally in the right way, but some people have not been taking enough note of our warnings not to cross rivers in flood because the flow is much stronger than usual,” Aritiana said.

The storm has damaged infrastructure, with many roads cut by rising waters, landslides and collapsed bridges.

Nearly 33,000 people have had to leave their homes in the Boeny region, in the northwest of the island. Locals say the prices of basic foodstuffs have skyrocketed.

“Prices of vegetables and rice increased a lot after the storm" with the cost of tomatoes quadrupling, said Véronique Mamitiana, a teacher in the city of Mahajanga. "The merchants say it's because the national road is cut," she said.