NAIROBI, Kenya (AP) – Heavy rains and deadly floods that have hit Kenya since March are the country's most devastating in recent years.
Heavy rains have left at least 169 people dead and at least 91 missing, according to the latest government figures.
In the most tragic single incident, at least 48 people were killed on Monday when water poured from a blocked river tunnel beneath railway tracks in southwestern Kenya, causing flash floods. 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 patterns, anthropogenic climate change, and natural weather phenomena.
It explains how they combined to cause a deadly deluge.
What is the “long rain” season in Kenya?
Kenya and other parts of East Africa have two main rainfall seasons: the “long rain” period from March to May and the “short rain” period from October to December.
The “long rain” season is when most of the country's average annual rainfall occurs. It is characterized by torrential rains, which can last until June.
The Kenya Meteorological Department has predicted this year's “long rains” season, with above-average rainfall in many parts of the country and occasional storms in some parts. It also warned of flash floods, landslides, mudslides and other impacts.
Last year's “short rain” season brought severe storms to many parts of the country, especially in November. According to the Bureau of Meteorology, Lamu, Mombasa and Garissa counties received nearly three times the long-term average rainfall.
Why is the rain so strong this time?
The frequency, pattern and intensity of rainfall in Kenya is influenced by naturally occurring climate systems such as the Indian Ocean Dipole.
The Indian Ocean Dipole is a change in sea surface temperature in which the western Indian Ocean becomes warmer than average and the eastern Indian Ocean becomes colder than average. There are positive phase, neutral phase, and negative phase.
The positive phase causes heavy rains in areas of the western Indian Ocean, such as Kenya, and droughts in Indonesia and Australia.
Joyce Kimutai, a researcher at Imperial College London, said that while many people associate the current floods with the naturally occurring El Nino phenomenon, research shows that this climate phenomenon has little to do with rainfall in East Africa during the “long rain” period. It has been shown that there is no impact.
El Niño is a warming of the oceans over the Pacific Ocean that can change the routes of storms and cause heavy rains in some parts of the world and droughts in others.
However, in Kenya's case, he said the positive impact of the Indian Ocean Dipole and climate change likely explain the ongoing flooding-inducing rainfall.
A hotter atmosphere warms the oceans, increases evaporation, and allows the air to hold more moisture, which can lead to more intense rainfall.
In a December analysis, Kimtai and colleagues from World Weather Attribution, a group of scientists that analyzes whether climate change plays a role in extreme weather events, concluded that last year's “short rain” season in Kenya was man-made. They discovered that climate change was the cause. It will be up to twice as strong in other parts of eastern Africa.
When will the “long rain” end?
In recent years, it has become difficult to predict Kenya's long-term weather, as the onset and duration of the dry and rainy seasons have become increasingly variable.
The Kenya Meteorological Department expects the “long rain” season to continue into June.
In its latest seven-day weather forecast released on Monday, the ministry said rain will continue in several parts of the country, with heavy rain possible in six regions, and flooding in low-lying areas and areas. Stated. A landslide that occurs on a steep slope.
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