Africa: Annual rainy season underway in the East Africa region through June

Event

Eastern Africa's annual rainy season will run from April to June bringing an elevated potential for flooding and landslides/mudslides regionwide. The affected area includes Kenya, Uganda, Burundi, Rwanda, and Tanzania. Forecast models indicate about average rainfall is forecast across Rwanda and Burundi. As of April 14, at least 2,053 people were displaced in the coastal areas of Bujumbura and Rumonge provinces in Burundi while about 1,088 homes were damaged nationwide. Additionally, above-average rainfall is forecast for Uganda and Kenya, while Tanzania is forecast to experience a rainy season ranging from average to above-average.

Hazardous Conditions
Heavy downpours, flooding, and landslides could affect business, transport, and utility services in many areas. Localized disruptions could persist well after hazardous events have concluded; floodwaters may take days to subside, and debris from mudslides may take weeks to be cleared. Rural communities and informal settlements often sustain the greatest damage and casualties during such events due to poor infrastructure.

The risk of flooding is highest in low-lying communities near watercourses in recognized floodplains. Eastern Africa has several major rivers and lakes, including the White Nile River and Lake Victoria, that could flood during periods of intense rainfall. Flash floods, which can occur with little to no warning, often pose a threat to communities downstream of major rivers, or dams in the event of structural failure. Urban flooding is possible in areas with poorly maintained or inadequate drainage systems, while storm surges may trigger flooding in coastal areas. Landslides and mudslides are possible in hilly and mountainous areas.

Tropical systems, including tropical depressions and cyclones, may pose additional threats during the rainy season. Tropical systems usually prolong or aggravate disruptions already caused by monsoon rainfall.

Transport
Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas, especially in rural areas, where infrastructure is already of a poor standard. 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. As of April 14, local authorities in Bujumbura closed the Avenue de la Plage route due to increasing water levels at Lake Tanganyika, while some businesses were forced to shut down. Parts of the Avenue de la Plage located between the Terrain Tempete area and the city port have already been damaged by flooding causing disruptions across the city.

Severe weather could trigger flight delays and cancellations at domestic and international airports. Authorities may temporarily suspend port operations if strong winds trigger hazardous sea conditions. 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; some businesses might not operate at full capacity because of flood damage to facilities, possible evacuations, and some employees' inability to reach work sites.

Health
The threat of disease outbreaks is elevated during the rainy season. Backflow from drains that has 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 waterborne diseases. Exposure to contaminated water from inundated industrial sites, sewer systems, and septic tanks also poses a significant health threat.

Advice

Monitor local media for updates and advisories on weather conditions. Confirm all transport reservations (air, ground, and maritime) prior to travel. Make allowances for possible supply chain disruptions throughout the rainy season, particularly in areas affected by flooding and or/landslide events.

Avoid low-lying areas near streams, rivers, and other bodies of water, such as reservoirs and coastlines, due to the threat of flooding. Do not drive on flooded roads. Exercise caution in elevated terrain due to the threat of landslides and mudslides. Charge battery-powered devices when electricity is available; restrict the use of cellphones to emergencies only during periods of severe weather. Take precautions against insect- and waterborne diseases. Keep any necessary medications in a waterproof container.

Resources

Kenya Meteorological Department
Uganda National Meteorological Authority
Rwanda Meteorological Agency
Tanzania Meteorological Agency