The French Indian Ocean region of Mayotte was hit by even heavier rains, causing flooding and mudslides, a month after Cyclone Chido destroyed large parts of the islands and killed dozens of people.
The archipelago has been put on maximum alert due to another storm on Sunday morning. Authorities have warned of violent winds, flash floods and landslides.
Videos on social media show downed power lines and some flooding. Local TV reported that the southern village of Mbuini, the only settlement untouched by Cyclone Chido, was under water.
The latest storm, Dikeladi, made landfall in northern Madagascar on Saturday, killing at least three people.
By 09:00 GMT on Sunday, the storm had moved about 100 kilometers (62 miles) south of Mayotte, according to forecaster Meteo-France.
“The very heavy rains are beginning to subside,” Mayotte Prefect François-Xavier Beauville told French news channel BFMTV.
They are causing the first floods “and relatively significant mudslides” across the region, he added.
The prefect said the island was likely to remain on red alert until Monday evening, as heavy rain was expected to continue after the storm passed.
BFMTV reports that at least 14,500 people have taken shelter in emergency shelters to avoid the storm.
As of Sunday afternoon, the storm was moving away from Mayotte, Meteo-France reported. The system is expected to gradually intensify to tropical cyclone status during the next 24 hours as it approaches the coast of Mozambique.
Current forecasts do not foresee landfall in Mozambique, but the Nampula region is still expected to experience “very degraded conditions”, forecasters said.
Mozambique is also recovering from Cyclone Chido, which killed 120 people in the country.
In Mayotte, one of the poorest parts of France, many residents live in bush towns.
The archipelago officially has 320,000 inhabitants, but authorities estimate that around 100,000 to 200,000 undocumented immigrants may also live there.
On December 14, Cyclone Chido became the worst storm to hit Mayotte in 90 years, bringing winds of 260 km/h (160 mph) and leveling areas where people lived in shacks with metal roofs.
Initial reports said several hundred people were killed, but the number was later revised down to 39.