NAIROBI, Kenya (AP) — Torrential rains and deadly floods that hit Kenya since March have been among the most catastrophic the country has seen in recent years.
At least 169 people have died due to heavy rains, and at least 91 are missing, according to the latest government figures.
In the most tragic event, at least 48 people were killed on Monday after water rushed through a blocked river tunnel under a railway line in southwest Kenya, causing a flash flood. The rains displaced more than 190,000 people and damaged roads and other infrastructure.
The devastating rains are the result of a combination of factors, including the country’s seasonal weather conditions, man-made climate change as well as natural weather phenomena.
Here’s how they combined to create the deadly flood.
Residents rescue a surprised woman during heavy rains in the Mathare neighborhood of Nairobi, Kenya, April 24, 2024. (AP Photo/Andrew Kasuku)
WHAT IS THE “LONG RAIN” SEASON IN KENYA?
Kenya and some other parts of East Africa have two main periods of rain: the “heavy rains” season from March to May, and the “small rains” season from October to December.
The “long rains” season is when most of the country’s average annual precipitation occurs. It is often characterized by torrential rains, and sometimes lasts until June.
In his forecasts For this year’s “long rains” season, the Kenya Meteorological Department has forecast above-average rainfall in many parts of the country, with occasional storms in some. It also warned of flash floods, landslides, mudslides and other impacts.
Last year’s “short rains” season was characterized by severe storms in many parts of the country, particularly in November. Lamu, Mombasa and Garissa counties received almost three times the long-term average rainfall, according to the weather service.
A displaced woman sits on a sofa in front of her flooded house, after heavy rains in the Mathare area of Nairobi, Kenya, April 24, 2024. (AP Photo/Brian Inganga)
WHY IS THE RAIN SO INTENSE THIS TIME?
The frequency, pattern and intensity of rainfall in Kenya are influenced by natural climate systems such as the Indian Ocean Dipole.
The Indian Ocean Dipole is a variation in sea surface temperatures that makes the western Indian Ocean warmer than average and then colder than average than those in the eastern Indian Ocean. It has positive, neutral and negative phases.
The positive phase causes heavy rainfall in areas west of the Indian Ocean, such as Kenya, and droughts in Indonesia and Australia.
While many people have linked the current floods to the natural weather phenomenon El Nino, research shows that this climate event has little influence on rainfall in East Africa during the “long rains” season, Joyce said Kimutai, research associate at Imperial College London.
El Nino is the warming of the ocean over the Pacific Ocean, which changes the paths of storms and can cause heavy rainfall in some parts of the world and droughts in others.
But in the case of Kenya, it is very likely that the positive Indian Ocean dipole and climate change explain the ongoing flood-causing rainfall, she said.
Warmer oceans caused by a warmer atmosphere increase evaporation, and air holding more moisture can produce more intense precipitation.
In analysis In December last year, Kimutai and his colleagues at World Weather Attribution, a group of scientists who analyze whether climate change played a role in extreme weather, found this Human-caused climate change made last year’s “short rains” season in Kenya and other parts of East Africa up to twice as intense.
Floodwaters are visible in Ombaka village, Kisumu, Kenya, April 17, 2024. (AP Photo/Brian Ongoro)
WHEN WILL THE “LONG RAIN” END?
Predicting long-term weather conditions in Kenya has become difficult in recent years as the onset and duration of the dry and wet seasons increasingly change.
Kenya Meteorological Department waits the “long rains” season will continue until June.
In its latest seven-day weather forecastAccording to the statement released on Monday, the department expects rainfall to continue in several parts of the country, with heavy downpours likely to occur in six regions, as well as flooding in low-lying areas and landslides. terrain on steep slopes.
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