NAIROBI — Heavy rains over the past week triggered floods across Kenya that killed 18 people and affected more than 54,000 households nationwide, according to police and the Interior Ministry. Most of the deaths were attributed to drowning, police said.

Approximately 6,000 of the affected households are in Nairobi, according to the Interior Ministry. Dozens of schools and hospitals across the country have flooded, and 17 roads have been cut off.

Landslides were reported in Tharaka Nithi, Elgeyo-Marakwet, and Kiambu counties in central and eastern regions of the country, police said. Mudslides have forced thousands of people to move from the western Rift Valley area, and police said the mudslides are displacing households and causing damage to property and infrastructure.

People living downstream of the Tana and Athi rivers have been urged to move to higher ground as water levels in hydroelectric dams rise. Local media reports showed streets in Nairobi overflowing with water, with cars and pedestrians wading through floodwaters.

Traders in the Makongeni and Ruai neighborhoods of Nairobi staged protests on Sunday over poor road conditions during the rains, saying it was affecting their businesses. The Kenya Meteorological Department warned that enhanced rainfall is expected to continue in the first two weeks of May, and that the rains posed health risks in the form of waterborne diseases and that damage to crops and farmland across the country was likely.

Kenya is currently in its seasonal March to May rain season, which usually peaks in the first half of May. Heavy rains began in March at the start of the rainy season, and by the end of that month more than 100 people had died due to the rains. This is the second time in less than two months that parts of the country have experienced deadly floods, after floodwaters in parts of Nairobi killed at least 37 people in March.

"Across African cities, water extremes—too much during intense rains and too little during droughts—are driving increasingly severe impacts. Cities must adapt rapidly to this new water volatility," said Fruzsina Straus, head of Disaster Risk Reduction for the United Nations Environment Programme.