In many lakes of the world, most of the waters come in and go out through rivers.
But for the largest lake in Africa, Lake Victoria, bordering Kenya, Tanzania and Uganda, most of the water feeding the lake is directly from the deadly storms occurring at night and early morning but not the rivers.
Deadly, intense thunderstorms build upon Lake Victoria at night as fishers go fishing.
The International Red Cross estimates that annually, between 3,000 and 5,000 fishers lose their lives in the violent storms.
Homa Bay Beach Management Unit chairman Edward Oremo told the Star that the storms are known to occur between April and May during heavy rainfall season and August to September during short rains. But in 2019 alone, extreme storms occurred from December 2019 to May 2020, with extreme rainfall.
"The storms have become unpredictable and violent. It's resulted in reduced catch, injuries, loss of fishing gears and vessels, and lost lives. The water levels have also risen," Oremo says.
NEED FOR MONITORING
Lake Victoria, the Nile's primary source, is a big, circular-shaped and relatively shallow lake, much of whose water is lost through evaporation.
Around Lake Victoria, it rains over land late in the afternoon and towards early night. But in the lake, it rains past midnight and early morning, when the fishers are fishing or arriving at the landing sites.
In Homa Bay county alone, Oremo approximates the losses at Sh350 million in the last two years. The losses are attributed to boats submerging, lost engines, boat breakage and landing site damages.
Abubakar Babiker, a climate scientist at the IGAD Climate Prediction and Application Centre, told the Star the Indian ocean is warming faster than any other part of the ocean system.
In 2019, warming caused an intense and increased number of tropical cyclones in East Africa, resulting in exceptional flooding.
"In the past 40 years, October to December 2019 was the third-wettest season for the East African region due to the Indian Ocean dipole. This saw Lake Victoria record the highest water level since records began," Babiker says.
John Marsham, a meteorologist with the University of Leeds, told the Star that with climate change, rainfall over East Africa and storms at Lake Victoria are projected to intensify.
"As the air becomes warmer, it can hold more water, allowing extreme rainfall to increase. It also provides more energy to the storms, resulting in more intense storms in a warmer climate," Marsham says.
However, Lake Victoria lacks an effective early warning system to protect those who depend on it, says Kisumu Meteorological Services director Paul Oloo.
Climate models projecting East African rainfall indicate increased rainfall in future. Hence, the Meteorological department requires improving the lakes observation for the rising water and storms to aid future planning.
As the water rose, the Met could not monitor the rising water levels due to lack of an effective monitoring system. Oloo says the department requires a weather surveillance radar near Kisumu to clearly monitor how the storms form and their trajectory to inform the fishers on time of incoming danger.
Wim Thierry, a climate scientist working at the University of Brussels, says, "Setting up the radar is fantastic at monitoring the storms but very expensive to maintain and run. It also requires high expertise to run, so it is critical to have these types of machinery running and the funding to do so."
FUNDING PROBLEMS
Oloo says lack of funds has hindered the department from acquiring a radar and hindered repair and servicing of existing weather infrastructure.
Thierry told the Star that an important data source on Lake Victoria observed via satellite is freely available online. Though it can be accessed using open-source software tools, the expertise to access it is lacking.
"The challenges are huge to operate such data and develop a warning system, as it might require the use of a supercomputer or artificial intelligence technical expertise to access and forecast the information from the satellite," Thierry said.
On the bright side, a three-year (2017-20) High Impact Weather Lake System (Highway) project has improved access to weather information along the Lake Victoria Basin.
The project brought together the National Meteorological and Hydrological Services of Kenya, Rwanda, Tanzania, Uganda and the UK and the US National Center for Atmospheric Research. It is managed by the World Meteorological Organisation and funded by the UK Department for International Development.
"Fishers wanted information on wind speed, visibility, the direction of waves, and rainfall availability, which KMD provides. But they needed information on lake current and lake temperature, but we do not have an observation system and we do not provide the information," Oloo says.
The Met director says his department lacks a local monitoring system over the lake and depends on Uganda and Nairobi's satellite monitoring.
"The information we are giving the fishers is based on the information observed from the regional and international services through satellite," he says.
Oloo says to effectively plan and minimise the deaths and losses impacting the fishing community at Lake Victoria, investment is needed in an effective weather monitoring infrastructure by the government.
Additionally, the observed radar imagery needs interpretation, hence effectively interpreting the observation into forecasts that institutions and fishers can use.
Brussels models show the extreme thunderstorms that today occur only once every 15 years will, with future climate projections, occur almost every year by the end of the century, with continued emission of massive greenhouse gases into the atmosphere.
Thierry believes it is important to invest in understanding how the lake will change in the long term as rainfall and temperatures rise. "This is vital in understanding how the thunderstorms change and for future planning purposes."
Edited by T Jalio