Met department warns of 99% possibility of El Niño

The Kenya Meteorological Department has warned of a 99 per cent likelihood of high rainfall across parts of the country as El Niño returns this year.

El Niño is characterised by above-average warming of the ocean surface in the central and eastern tropical Pacific Ocean, and during this period east winds blow weaker than normal.

The phenomenon typically occurs every 3 to 5 years and causes excess rainfall and flooding in the East Africa region.

Addressing journalists in Nairobi on Wednesday, the weatherman said heavy continuous rainfall is expected in the Lake Victoria Basin region, Kisii, Elgeyo Mrakwet, Bungoma, Trans Nzoia, West Pokot, Vihiga, Laikipia, Nakuru and Narok counties.

The rains will begin in September and go on until January. They are expected to peak in October.

In the north-western counties of Turkana, Marsabit and Samburu, the met department said occasional rainfall above the long-term average for the season is expected.

“In the highlands east of the Rift Valley, Nairobi included, rainfall is expected throughout the season above the season's long-term average. The rainfall will be well distributed in terms of space,” said the department.

In the lowlands, an above-long-term average for the season is expected while in the north-eastern counties, occasional rainfall of an amount slightly above average for the season will be experienced. Wajir and Mandera counties will get the highest rainfall.

In the Rift Valley region, flooding is likely to occur in Gilgil, Narok town and Suswa while the coastal towns of Mwatate, Tana River delta and Mwatate have also been identified as high-risk areas.

Others include Lodwar and Lokichar in north-eastern Kenya where flash floods are expected to be prevalent due to a high number of seasonal rivers, as well as major urban centres like Nairobi, Naivasha, Nakuru and Mombasa.

At the same time, Kenyans have been warned of landslides in parts characterised by water-logged soils such as West Pokot,  Kericho, EIgeyo Marakwet, Mt Elgon, Narok, Nakuru, Baringo, Murang'a and areas around Kilungu in Makueni County.

La Niña involves the cooling of sea-surface temperatures across the east-central equatorial Pacific, and the east winds are stronger.

The world experienced a third consecutive La Niña event in 2022 and early 2023, a rare occurrence that has happened only twice since 1950.

La Niña events are commonly associated with wetter conditions in Australia and drier conditions in the United States of America, South America and East Africa.

In East Africa, the effects on cereal production were particularly devastating, with several countries experiencing multiple seasons of failed crops that triggered famine alerts in Somalia in the first half of 2022.

According to FAO, the 2023 La Niña event officially ended in March 2023.