Kenya: Response operations ongoing after dam failure leads to flash flooding near Mai Mahiu, Nakuru County, as of April 29

Response operations are ongoing after a dam failure triggered flash flooding near Mai Mahiu, Nakuru County, early April 29. Floodwaters and debris swept through the village of Kamuchiri, destroying homes and trapping residents in the mud. Authorities have reported at least 42 fatalities, and more than 100 others have been injured; casualty figures could rise in the coming hours and days as response operations continue. The road from Nairobi to Mai Mahiu has been cut off due to debris, which has hampered response efforts. Further heavy rainfall is forecast in the region over the coming days, and the additional downpours could trigger further flooding and landslides. Localized disruptions are expected to continue in the vicinity of Mai Mahiu over the coming days due to ongoing response and recovery operations.

Further sustained heavy rainfall could trigger additional flooding in low-lying communities near rivers, streams, and creeks. Urban flooding is also possible in developed areas with easily overwhelmed stormwater drainage systems. Sites located downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides are possible in hilly or mountainous areas, especially where heavy rainfall has saturated the soil.

Authorities could issue mandatory evacuation orders for flood-prone communities over the coming days. Disruptions to electricity and telecommunications services are possible where significant flooding or landslides impact utility networks.

Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas. Ponding on road surfaces could cause hazardous driving conditions on regional highways. Authorities could temporarily close some low-lying routes that become inundated by floodwaters. Flooding could block regional rail lines; freight and passenger train delays and cancellations are likely in areas that see heavy rainfall and potential track inundation.

Localized business disruptions may occur in low-lying areas; some businesses might not operate at full capacity because of flood damage to facilities, possible evacuations, and some employees' inability to reach work sites.

Flooding could heighten the threat of disease outbreaks. Backflow from drains mixed with floodwaters can become trapped in open areas when inundations recede. These stagnant pools often become a breeding ground for mosquitoes and bacteria, increasing the incidence of insect- and water-borne diseases. Exposure to contaminated water from inundated industrial sites, sewer systems, and septic tanks also poses a significant health threat.