Facts about El Nino

A boda boda rider is overwhelmed as he attempts to cross a flooded section of Isiolo town in April 2018.[Bruno Mutunga, Standard]

In the last few weeks, talks of El Nino rains have topped social media trends, after it was predicted to begin in October.

Last evening, the Kenya Meteorological Department reaffirmed that the El Nino rains still remain a reality in the September to December weather forecast.

"Kindly take note that the El Nino phenomenon remains in effect. As a result, it is expected that both the month of October and the entire season is likely to receive above-average rainfall, which remains linked to the ongoing El Nino event," Kenya Met said.

In this explainer, The Standard seeks to understand what the El Nino phenomenon really is.

So what is El Nino?

El Nino is a natural climate pattern that originates in the Pacific Ocean along the equator, and its impact is felt all over the world.

It is part of a natural climate phenomenon called El Nino Southern Oscillation (ENSO) that has two opposite states namely El Nino and La Nina.

The weather partner is usually declared when sea surface temperatures in the central and eastern equatorial Pacific Ocean rise to at least 0.5C above the long-term average.

Normally, the surface water in the Pacific Ocean is cooler in the east and warmer in the west but the effect starts when the trade winds start blowing east to west as heat from the sun progressively moves in the eastern direction.

El Nino effects would occur when the winds slow down or reverse sending warm surface waters eastwards.

When was it first witnessed?

The event was first observed in the 1600s in Peru where it was nicknamed 'El Nino de Navidad' meaning Christ Child in Spanish.

El Nino events are normally associated with increased amounts of rainfall in parts of the southern United States, South America Central Asia, and the Horn of Africa.

In Kenya, the phenomenon was last experienced between May 1997 and February 1998 when it resulted in heavy rainfall and floods.

Consequently, in 2015 the El Nino prediction had a higher index but led to lower rainfall that caused less effects compared to the scientists' predictions.

The phenomenon usually occurs every two to seven years and the effects last for a period of nine to 12 months.

It's associated with a lot of effects that have seen the government and several ministries call for proactive measures to deal with the effects before the onset.

Mitigation measures

Due to the anticipated long rains, the weatherman has warned that it might cause flooding, landslide among others advising people to be cautious.

Here are some mitigation measures that can help in preparations for the heavy rains.

Ensure that the water drainage system at your home is functioning properly, allowing water to flow away from the house.

Clear any accumulated trash or debris in the compound that could obstruct drainage, enabling smooth water flow.

Due to the likelihood of flash floods following heavy rains, it is advisable to avoid areas prone to flooding whenever possible. If feasible, consider relocating to safer grounds before the onset of the rains

Stay alert by keeping up with the latest weather updates. This will provide timely information and allow you to take necessary precautions.

The Intergovernmental Authority on Development Climate Prediction and Applications Centre (ICPAC) scientists predicted a greater than 80 percent chance of above-average rainfall in southern Ethiopia, eastern Kenya, and southern Somalia and possible dry conditions for parts of Uganda and South Sudan.