People are being told to move to higher ground as flooding rages in northern Mozambique, which has been battered by Cyclone Kenneth over the last three days.
With more rain forecast for the coming days, hundreds of thousands of people are at risk.
One person was killed as the flood waters began to cut off the region’s main city on Sunday.
Residents in Pemba begged passing cars for help as the torrential rain continued.
They shouted “Help us, we are losing everything” as the rushing waters flooded their homes.
Women and girls were pictured fighting a losing battle to scoop away the torrent with buckets.
Rescue teams mobilised as homes began to collapse and United Nations workers said in a tweet: “We are unfortunately expecting devastating floods.”
Cyclone Kenneth arrived in the region just six weeks after Cyclone Idai battered central Mozambique, killing more than 600 people.
Twice as much rain could fall in the new storm, the UN World Programme has said.
Forecasters say as much as nine inches – about a quarter of the average annual rainfall – could fall over the next few days and up to four inches are forecast in the next 24 hours, according to Mozambique’s meteorological institute.
Pemba resident Michael Fernando, 35, said: “I have never seen such rains in my life.”
It is the first time in recorded history that the southern African nation has been hit by two cyclones in one season – fuelling concerns that climate change could be to blame.
At least five people died after Kenneth roared in on Thursday evening, according to the authorities.
More than 160,000 people have been affected in the largely rural region with many already exposed and hungry.
Some 35,000 homes in parts of Mozambique’s northern Cabo Delgado have either been destroyed or badly damaged.