Tens of thousands of people are still without access to water in Mayotte after the French Indian Ocean territory was devastated by Cyclone Chido, as rescuers race to find missing people.

Preliminary figures from France’s interior ministry report 22 people have died, but Mayotte’s prefect has warned the toll could rise to thousands.

Health workers are concerned infectious diseases could spread, as residents have reported clean drinking water shortages and shops are rationing supplies. More aid is due to arrive on Wednesday.

Islanders spent a first night under curfew between 22:00 local time on Tuesday and 04:00 on Wednesday (19:00 and 01:00 GMT) as part of measures to prevent looting.

“Everyone is rushing to the stores for water. There is a general shortage,” Ali Ahmidi Youssouf, 39, told AFP on Wednesday while walking with a few bottles in his hand in the community of Pamandzi off the archipelago’s main island.

Half the territory remains without power. The authorities have said their priority is to get damaged water plants back up and running.

On Wednesday, authorities said the water system had been partially re-established and they hoped 50% of the island’s population will have access to water by the evening.

The French government said 120 tonnes of food are due to be distributed on Wednesday, while President Emmanuel Macron is scheduled to visit Mayotte on Thursday.

Mayotte is one of the poorest parts of France, with many of its residents living in shanty towns.

Chido – the worst storm to hit the archipelago in 90 years – brought wind speeds of more than 225km/h (140mph) on Saturday, flattening areas where people lived in shacks with sheet metal roofs and leaving fields of dirt and debris.

“It was like a steamroller that crushed everything,” Nasrine, a teacher who did not give her last name, told AFP in her destroyed neighbourhood in Pamandzi.

Another witness to the storm told Reuters that roofs “flew away as if they were pieces of paper”.

“A gust of wind broke the window and tore a wooden plank. The planks were 2m by 3m (6.5 by 9.8ft),” said Diego Plato, a photographer with the 5th Foreign Regiment of the French Legion.

He added that many of the legion’s buildings cannot function anymore because they no longer have roofs.

Rescuers are now searching for survivors in the ruins, such as in the capital Mamoudzou, while trying to unblock roads and clear rubble and downed trees.

On Wednesday morning, Mamoudzou residents whose houses survived the storm hammered metal sheets over damaged roofs.

Francois-Xavier Bieuville, Mayotte’s prefect, previously told local media the death toll could rise significantly once the damage was fully assessed.

He warned it would “definitely be several hundred” and could reach thousands.

Chido also killed at least 45 people in Mozambique, and at least seven in Malawi, according to those countries’ disaster management departments.

Officials have said that Mayotte’s relatively low official toll is due to many areas being inaccessible and some victims already being buried.

The difficulty is compounded by uncertainty about Mayotte’s population size.

The territory officially has 320,000 inhabitants, but authorities estimate about 100,000 to 200,000 undocumented migrants may be living there.

Initial figures from the interior ministry show that 1,373 people in Mayotte were injured.

France’s newly-instated Prime Minister François Bayrou told parliament on Tuesday that there were “200 badly wounded and 1,500 wounded in a relative state of urgency”.

“I have never seen a disaster of this magnitude on national soil,” Bayrou said later in a post on X.

“I think of the children whose houses have been swept away, whose schools have been almost all destroyed and whose parents are extremely distraught.”

The government said it was sending in supplies via an air bridge from its other Indian Ocean territory, Reunion Island.

On Wednesday, 100 tonnes of food are due to be distributed on the larger island of Grand-Terre in Mayotte, while 20 tonnes are set to be handed out on the smaller island of Petite-Terre.

A French navy support and assistance vessel is also due to arrive in Mayotte on Thursday morning with 180 tonnes of freight on board.

The ferry linking Mayotte’s two main islands resumed services on Wednesday, allowing some people caught out by the storm to return to their families.

“I haven’t heard a word from my employees in five days,” a landowner taking the ferry, who declined to give his name, told Reuters. “It’s back to the Stone Age.”

Meanwhile, in Malawi – where Chido headed after moving through Mayotte – authorities say seven people were killed.

Up to 20 of the country’s 29 districts have experienced “mild to severe damages” affecting about 35,000 people, a statement from the disaster management department said.

The number of deaths and level of destruction is lower than in neighbouring Mozambique where authorities put the death toll at 34.

Experts say seasonal storms like Chido are intensifying in strength due to warmer ocean waters.

The cyclone poses another challenge for the government following months of political turmoil, with Bayrou appointed last week following the ousting of former Prime Minister Michel Barnier.