Nigeria's meteorological agency, NiMet, has warned that 19 states face an elevated risk of flash flooding as the rainy season intensifies, a span that stretches from Zamfara in the north-west to Bayelsa in the south, and takes in some of the country's most densely populated urban centres, including Lagos, Rivers, Oyo, and Anambra.
NiMet's advisory flagged several direct consequences residents should prepare for, including flooded roads and blocked drainage channels, power outages caused by flooding of electrical infrastructure, and a heightened risk of waterborne diseases, including cholera and typhoid, in areas where floodwater mingles with sewage or waste.
The risk is compounded in cities across the country by rapid and largely unplanned urban expansion, drainage networks that have not kept pace with population growth, and the widespread practice of building on low-lying or flood-prone land.
The warning is rooted in a seasonal pattern familiar to weather scientists. After months of dry conditions, soil across much of Nigeria becomes compacted and hard, losing much of its natural capacity to absorb rainfall.
When the early rains arrive, water cannot percolate into the ground quickly enough, and instead accumulates on the surface, flowing into streets, compounds, and drainage channels faster than the infrastructure can handle.
The nineteen states flagged by NiMet are: Zamfara, Nasarawa, Kwara, Oyo, Lagos, Ogun, Ekiti, Delta, Imo, Anambra, Enugu, Ebonyi, Akwa Ibom, Cross River, Rivers, Edo, Ondo, and Bayelsa.
