A man raises a red flag, signaling severe weather, on the shores of Lake Victoria.
Samuel Gatei/WMO

Science is Society

With the sight of a color-coded flag or the touch of a mobile phone button, fishers and fish traders along the vast shores of Lake Victoria now know when it’s ideal to postpone a fishing trip or to buy less fish for the day.

Four years of testing an early-warning system (EWS) to inform fisherfolk in East Africa of approaching high-impact weather events on Lake Victoria recently concluded. The High Impact Weather Lake System (HIGHWAY) project successfully demonstrated how improved weather, water, and climate services can save lives and livelihoods, as well as support socioeconomic development of vulnerable communities.

In 2017, the HIGHWAY project started on Lake Victoria, the largest of the African Great Lakes and the largest inland fishery on the continent. Lake Victoria’s 7,145-kilometer shoreline is shared by Kenya, Tanzania, and Uganda. Fisheries employ between 500,000 and a million people from those countries as well as from neighboring nations Burundi and Rwanda and harvest about a million metric tons of fish every year.

Lake Victoria’s size (it is the world’s second-largest freshwater lake, behind only Lake Superior in North America) allows it to generate its own weather patterns, sometimes suddenly and with human and economic casualties. According to its website, HIGHWAY aimed to “enhance the resilience of African people and economic development to weather and climate related shocks, with an initial focus on the Lake Victoria Basin.” The project was funded by £4.5 million from the U.K. Department for International Development, under Weather and Climate Information Services for Africa.

“HIGHWAY was an ambitious project that spanned the entire weather and climate services value chain—improving surface-based observations, developing products to improve forecasting quality, and providing training on impact-based forecasts and warnings in the Lake Victoria basin,” said Jay Wilson, head of the Project Management and Implementation Division at the World Meteorological Organization (WMO).

Satellite image of Lake Victoria
Lake Victoria, the world’s second-largest freshwater lake, can generate its own weather systems. Credit: NASA

“Thanks to the strong commitment, partnership, and collaboration from all international and regional partners, we succeeded in increasing access to and use of codesigned early warnings that improved the lives of communities living in the Lake Victoria basin,” said Wilson.

“This early-warning system is a good thing for Lake Victoria, because according to Red Cross statistics, about 5,000 people were dying annually [due to storms, strong winds, and large waves] prior to the year 2016. This figure does not include all the deaths that occur on the lake given that not all incidents are reported,” said Paul Oloo, Kisumu County director of meteorology and assistant director of the Kenya Meteorological Department.

Making the System

As part of the project, the National Meteorological and Hydrological Services (NMHSs) of Kenya, Rwanda, Tanzania, and Uganda cooperated in generating regular Lake Victoria weather forecasts and severe weather warnings.

HIGHWAY supported the increase in availability of meteorological data and observations throughout the Lake Victoria basin. Notably, the project contributed to the rehabilitation of upper air stations in Lodwar and Nairobi, Kenya; Entebbe, Uganda; and Dar es Salaam, Tanzania.

The project also contributed to the availability of such enhanced tools as high-resolution modeling, as well as products, including Rapidly Developing Thunderstorm (which detects, tracks, characterizes, and forecasts convective cells) and Convective Rainfall Rate (an algorithm based on the assumption that high clouds with a large vertical extent are more likely to be raining). Such products improve the accuracy of severe weather forecasting in the basin, explained Wilson.

Practical Outcomes

The HIGHWAY enhancements resulted in the Uganda National Meteorological Authority being able to provide updates of thunderstorms and heavy rain over Lake Victoria in real time. In Kenya and Tanzania, marine weather forecasts are now being disseminated specifically to fishing communities twice per day. The forecasting offices of all three NMHSs also share their published forecasts through a WhatsApp group.

A three-color traffic light flag system and notice boards are also used on beaches around the lake to describe the conditions expected during the forecast period.

The flag signals help people without smartphones, said Ibrahim Mengo, a fisherman in Uganda. “When I look at the forecast and see the flag is green, then I know it’s OK to go, but when [the flag is] red or orange, I know where I’m going is not safe and I decide whether or not to go.”

People on docked fishing boats on the shores of Lake Victoria
Fisherfolk are among the most threatened by severe weather on Lake Victoria. Credit: Samuel Gatei/WMO

Communication and Cooperation

Efforts supported by HIGHWAY addressed improving communication and cooperation in sharing meteorological data among organizations and communities. Severe weather forecasts, participants said, could be inconsistent: In some cases, fisherfolk did not receive any weather warning. In still other cases, the fisherfolk did not take received weather information seriously, and sometimes they did not understand the message itself, Oloo said.

“The early-warning information passed currently to [fisherfolk] is in a language and format that they can understand. Weather warnings were codesigned with them, standard weather messages developed jointly, and the weather information passed directly in its original format using the WhatsApp platform.”

In contrast, “the early-warning information passed currently to [fisherfolk] is in a language and format that they can understand. Weather warnings were codesigned with them, standard weather messages developed jointly, and the weather information passed directly in its original format using the WhatsApp platform,” Oloo said.

Innovations also included a “quick reference guide developed for translating standard weather terms to local languages,” he added.

Training sessions for forecasters, observers, and users in fishing communities have built trust in the forecasts. “Communities are more confident in using the weather information to plan fishing trips and other journeys on the lake,” said Wilson.

In establishing the regional early-warning system, standard operating procedures and impact-based warning methods were developed jointly by partner states. Representatives from those states joined daily teleconferences so they could agree on severe weather warning information, but each partner state disseminated weather advisories in its area of jurisdiction.

“We receive weather messages on our phones, and when you get an update, you send it to other people and put it on your WhatsApp status so that it can reach many fishermen,” said Mildred Shihanga, a fish trader in Kenya.

Saving Lives and Livelihoods

A smiling woman carrying a large basket of fish on her head walks away from Lake Victoria.
The fisheries on Lake Victoria generate more than a million metric tons of fish every year. Credit: Samuel Gatei/WMO

“I think the EWS system for Lake Victoria is a very good and important step to protect the lives and livelihoods of the communities that live around the lake,” said Nairobi-based climate scientist Abubakr Salih Babiker of the Intergovernmental Authority on Development’s Climate Prediction and Applications Centre, which provides climate services to 11 East African countries but is not part of the HIGHWAY project.

“The boats used by fishermen are small and have no access to weather forecasts, especially when they are in the water. Now, the EWS gives them the forecast before and while they are in the water using mobile technology,” Babiker said. “It also helps farmers to plan better. It will help in saving lives and livelihoods.”

Rumelia Joshua, a fish trader in Tanzania, agreed. “The information helps us because when we get notified about bad weather, we buy fish in small quantities and save money,” she said.

Scaling Up

WMO and other supporters of the HIGHWAY project plan to scale it up to encompass regional forecasting for all of East Africa, said Wilson.

Babiker said HIGHWAY owes its success to the cooperation of the partner states as well as to forecast products that focus on the lake itself as opposed to national systems. “In this way, you get better products and better user services. If you are a fisherwoman on the lake, you basically need the same information regardless of your country,” he said.

—Munyaradzi Makoni (@MunyaWaMakoni), Science Writer


Makoni, M. (2021), Forecasters navigate a highway to success around Lake Victoria, Eos, 102, https://doi.org/10.1029/2021EO158366. Published on 13 May 2021.

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