African SWIFT report on flooding and heavy rainfall in Kenya

Report by SWIFT Research Team from Kenya Meteorological Department (KMD)

Emmah Mwangi, John Mungai and Benard Chanzu report:

During the March-May (MAM) 2018 season most parts of Kenya have received enhanced rainfall, which was characterized by intense storms.  As at 26th April, 2018 much of the country had already received rainfall that was over 125% of the MAM Long Term Mean (LTM) as shown in Figure 1.

Figure 1: Rainfall total up to 26th April compared to the MAM long term Means

The heavy rainfall has caused flooding, landslides, loss of property and life in some parts of the country. Much of the flooding has occurred in urban and low lying areas and has been as a result of two factors, namely:  the intense rainfall events over most parts of the country and accumulated heavy and continuous rainfall in the upper catchment areas that are sources of some of the rivers that broke their banks.

The heavy rainfall can be attributed to three factors: firstly, at the beginning of the season (Early March) heavy rainfall over much of the country was caused by the presence of two tropical cyclones in the Indian Ocean; Dumazile and Eliakim. The Cyclones caused heavy rainfall by pulling in moisture from the Congo basin and creating a pressure gradient that pulled the North-South arm of the rainfall generating Inter Tropical Convergence Zone eastwards.

Secondly, for most of the season the Madden Jullian Oscillation (MJO) was conducive. The MJO is a band of convective clouds and rain moving west to east. The circulation occurs in various phases that can be either conducive or unfavorable for rainfall generation over Kenya. This time around, the circulation has been persistently been in the phases that are conducive for rainfall enhancement over Kenya and hence heavy rains that have pounded the country within the season. Thirdly, the warm Sea Surface Temperatures over the Western Indian Ocean sustained the convergence belt over the region.

Frequent flooding and droughts are part of the climatic variability in Kenya. However, these events have become more frequent and intense as a result of climate change which is being experienced globally. These events are projected to be more frequent and intense in future hence, there is need to institute effective adaptation and contingency plans amongst the vulnerable communities to ensure they are not severely impacted. There should be timely use of Early Warning information to minimize impacts associated with these extreme climate events. Awareness creation amongst the vulnerable communities on what needs to be done in case of the occurrence of these events need to be enhanced.

Research Posts available with African SWIFT

African SWIFT is now advertising for a number of research posts. See our Project News / Opportunities page for full details.

3 posts: Programme Science Director and two expert Research Scientists (ACMAD, Niamey, Niger) Deadline 20 April.

4 posts: Senior Research Scientist, Research Scientist and two Research Fellows (NCAS, University of Leeds, UK) Deadline 24 May.

2 posts: Postdoctoral Research Scientists (NCAS, University of Reading) Deadline 2 May 2018.

African SWIFT reports on recent floods in Kenya

SWIFT Researcher Emmah Mwangi from Kenya Meteorological Department (KMD) reports:

In March 2018 there have been two episodes of heavy rainfall in most parts of Kenya, which caused massive flooding in urban and low lying areas. Both episodes were caused by the presence of Tropical cyclones in the Indian Ocean; Dumazile and Eliakim. The effect of Cyclones in the Equatorial East African region is that they help pull in moisture from the Congo basin, and the gradient created by the  low pressure systems also pulls the North-South arm of the Inter tropical convergence zone Eastwards. In the recent past as storms have become more severe and frequent during the rainy seasons of March – May and October-December, flooding, and especially flash flooding in urban areas, has become more common.

It is likely that these events are linked to global warming on both global and local scales. Globally reports have indicated that the oceans are warming, and with the Indian Ocean being warm at the beginning of March this encouraged the formation of cyclones. Locally as temperatures rise the effect of urban heating has also magnified, and with this urban areas like Nairobi are getting more severe storms. Analyses of the future likelihood of extreme events occuring over the East Africa region have shown that such events are probably going to become more frequent and more severe.  Unless climate is factored into urban planning it is highly likely that we will see more flash floods occurring in urban areas.

The forecasts for both of the recent flooding events were very accurate both on short and medium range scales. Advisories for the heavy rains were prepared and sent out days before the events started providing advance warning of the expected heavy rains to disaster managers and the general public. As social media becomes more popular across Kenya Facebook and Twitter, as well as mobile apps such as Whatsapp and Telegram are used increasingly to reach a greater proportion of the general public.

The satellite images below show rainfall for 4th March 2018.

4 Mar 08.30
4 Mar 12.45
4 Mar 15.45








The satellite images below show rainfall for 15th March 2018.

15 Mar 07.45
15 Mar 12.45
15 Mar 15.45

GCRF African SWIFT Project Kick-Off Meeting

The NCAS – led Global Challenges Research Fund African Science for Weather Information and Forecasting Techniques (GCRF African SWIFT) project held their kick-off meeting in Dakar, Senegal from 13 – 17 November, 2017.

The project meeting in Dakar was an opportunity for the team to lay out the groundwork for the four-year project, which aims to improve tropical forecasting ability, build capacity within African forecasting agencies, and improve communication links to forecast users. The fulfilment of these aims will greatly benefit African populations and demonstrate forecasting capability in the wider developing world.

Find out more about the meeting here:

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