About two million people in northern Nigeria have been displaced after authorities opened the floodgates on two dams.
The flooding began suddenly when the gates on the Challawa and Tiga dams were opened, a spokesman for the Jigawa governor said.
The dams are in Kano state, but about 5,000 villages in neighbouring Jigawa state have been affected, he added.
Several states in northern Nigeria have been hit by floods this year.
It is not yet clear whether residents received a warning or if anyone was injured or went missing in the flooding.
The floodgates are normally opened every year during the rainy season.
Nigeria’s meteorological agency had previously forecast low rainfall in the north, warning that more than 12 million people could face food shortages as a result.
In a normal year, the water released from the dams flows into fields, irrigating crops of corn, rice and vegetables during the brief growing season.
Jigawa and Kano are part of the Sahel region, a belt of semi-arid land south of the Sahara desert.
In neighbouring Niger, millions are facing food shortages after a prolonged drought caused crops to fail. That was followed by severe flooding last month. Millions are now facing food shortages.