At least 48 people, including 17 minors, have died, dozens more are missing, and more than 110 are being treated in hospital following a dam failure in central Kenya on Monday 29 April 2024. The colonial-era Old Kijabe Dam, near the town of Maai Mahiu in Nakuru County (about 50 km to the northwest of Nairobi) gave way at about 3.00 am local time, following weeks of near-continuous heavy rain in the region, sending water coursing through the village of Kamuchiri, where it swept away people, homes, businesses, vehicles, and livestock.
The incident came amid a series of flooding incidents across East Africa, with more than 160 people known to have died and around 180 000 displaced by flood events in Kenya alone. In neighbouring Tanzania at least 155 people have died and over 200 more have been seriously injured. In Burundi more than 200 000 people have been forced to leave their homes due to flooding, and deaths have also been reported in Rwanda and Ethiopia.
East Africa typically has two rainy seasons, one lasting from March to May and the other from October to December. This year the early rains have been particularly severe, driven by a combination of a strong El Niño system and a Positive Indian Ocean Dipole phase, both of which are in turn fuelled by this years exceptionally strong global temperatures, which are a result of the rising levels of greenhouse gasses (carbon dioxide, methane, and water) within the Earth's atmosphere, a direct result of Human activities (although the entire continent of Africa is thought to be responsible for only 2-3% of all anthropogenic greenhouse gas emissions).
The El Niño is the warm phase of a long-term climatic oscillation affecting the southern Pacific, which can influence the climate around the world. The onset of El Niño conditions is marked by a sharp rise in temperature and pressure over the southern Indian Ocean, which then moves eastward over the southern Pacific. This pulls rainfall with it, leading to higher rainfall over the Pacific and lower rainfall over South Asia. This reduced rainfall during the already hot and dry summer leads to soaring temperatures in southern Asia, followed by a rise in rainfall that often causes flooding in the Americas and sometimes Africa. Worryingly climatic predictions for the next century suggest that global warming could lead to more frequent and severe El Niño conditions, extreme weather conditions a common occurrence.
Indian Ocean Dipole Phases are similar to the El Niño/La Niña climatic oscillation that affect the Pacific Ocean. Under normal circumstances equatorial waters off the east coast of Africa and west coast of Indonesia are roughly similar in temperature, however during a Positive Indian Ocean Dipole Phase the waters off the coast of Africa become significantly warmer. As the prevailing currents in the area flow west to east, this warm water is then pushed onto the shallower continental shelf off the East African coast, where it warms the air over the sea more rapidly, leading to increased evaporation (which fuels rain) and a drop in air pressure over the western Indian Ocean. This in turn drives air currents over the Indian Ocean to flow more strongly east to west, leading to higher rates of warming off the coast of Africa and more cooling off the coast of Indonesia, fuelling a feedback cycle that tends to remain through the winter season in any year when it forms. This leads to a particularly wet rainy season across much of East Africa, while much of Australia is at risk of drought (during a Negative Indian Ocean Dipole Phase the reverse happens, with drought in East Africa and flooding in Australia).
See also...
.png)