Floodwaters in central Somali left thousands of families displaced in Beledweyne, the city with the highest population density in the region.
The UN Office for the Coordination of Humanitarian Affairs (OCHA) reported the Horn of Africa nation to have "more than 460,000 people have been affected, including nearly 219,000 people who have been displaced", in early estimates.
Rising water level in Beledweyne forced a number of important facilities to close in the town including government offices and the town's main hospital.
Local resident Hussein Yusuf told The Associated Press that it was the "worst flood we have ever experienced", citing the size of the deluge and subsequent damage to property.
Residents fear a cholera epidemic and malaria outbreak if the floods continue.