In Hot Water

2024's Atlantic hurricane season has been full of surprises. West Africa's coast may explain why.

The worst Atlantic hurricanes often begin their destructive treks in the open ocean between West Africa and the Caribbean, an area that scientists appropriately call the “main development region.”

Here in this storm nursery, clusters of thunderstorms from the African continent feast on the ocean’s heat and begin to rotate. Marching west, they may spin into land and our history books.

---

As a nonprofit journalism organization, we depend on your support to fund more than 170 reporting projects every year on critical global and local issues. Donate any amount today to become a Pulitzer Center Champion and receive exclusive benefits!

---

All told, more than 80 percent of the Atlantic’s most powerful hurricanes were born in the main development region.

This includes hurricanes like Hugo 35 years ago, which caused about $23 billion in damage in South Carolina in today's dollars.

And Irma in 2017, which carried 185 mph winds in the Caribbean before cutting into Florida and swamping coastal South Carolina.

Meteorologists also see the Atlantic's main development region as a Rosetta stone of sorts: When seas there are warmer than normal, hurricane seasons tend to be more brutal.

Which is why meteorologists were so anxious about this year.

See a graphic depicting the path of all major hurricanes from 1989 to 2024.

In March, a severe heat wave in West Africa helped warm the oceans offshore. By June, ocean temperatures in the tropical Atlantic were as high as they typically get in mid-August. And by mid-August, they were 38 percent higher than the previous 10-year average.

“This just increases the fuel available to whatever storms might pass over it,” said Brian McNoldy, a tropical storm expert at the University of Miami.

Forecasters predicted an above-normal number of tropical storms, but then something unexpected happened in late August: a lull at the peak of the season. It was as if a giant lid had been placed on the Atlantic's hurricane cauldron. What was going on?

Meteorologists talked about their 2024 forecasts being a "bust." But a deeper look at the Atlantic’s main development region reveals a more nuanced story, one about migration of sea life and people and shifting currents in the ocean and the sky.

This story also carries a surprising twist that helps explain why some decades had fewer hurricanes and how a rapidly warming planet is adding even more twists this year.

Fishing for Answers

Senegal juts into the Atlantic like a sideways volcano, with the country's sprawling capital of Dakar on the peak, the African continent's westernmost point.

Off these shores, powerful sea currents from the north and south converge, then follow the trade winds west. This mix of cold and warm water created one of the world’s richest fishing grounds.

With this close access, Senegal's fishing industry has long been an important employer and source of food. Fishing villages dot the coast, including the community of Fass Boye, about 60 miles north of Dakar.

On a recent day, colorful pirogues lay on the beach hull-to-hull like the fish sold in nearby open-air markets. The long and narrow boats were made of wood, some painted the colors of Senegal's flag — green, yellow and red. Many carried the names of relatives, said Jeuwriñ Diop, who has fished these waters since the 1970s.

When he first went to sea, it was cool from December through March, he said, his mind going back in time. He and other fishermen used a net to haul in sardinella and similar species that liked this cool water “freshness,” he said. Sometimes, fishermen needed just a day on the water to bring in enough fish to make a living.

Now “you can spend a week or two at sea fishing with little or no success,” Diop said. The heat had taken away this freshness, and “all of these types of fish have fled because they cannot adapt.”

Fishermen have followed the migrating fish. Last year, a group of more than 100 men and boys left Fass Boye in a pirogue. They hoped eventually to make it to Europe, but winds blew them off course. The pirogue capsized. A fishing vessel found the boat drifting off the islands of Cape Verde with fewer than 40 survivors.

Diop and the fishermen of West Africa are not alone in feeling the effects of warmer seas. From Greenland to the Caribbean, temperatures in the planet’s oceans have risen steadily over the past three decades, a chronic fever caused in large part by the rapid rise in carbon dioxide and methane.

These greenhouse gases trap heat in the Earth’s atmosphere and prevent that heat from going into space. Instead, roughly 90 percent of that heat ends up in the ocean. As a result, sea temperatures globally are now at their warmest level in recorded history.

But temperatures are rising faster in some oceans than others, including the main development region between Africa.

Teams measuring sea temperatures off Senegal and the Mauritania border have seen increases of about 0.1 to 0.3 degrees Celsius (0.18 to 0.36 degrees Fahrenheit) per decade, said Massata Ndao, head of the Oceanography Division for the Senegal Ministry of Fisheries and Maritime Infrastructure.

Though small, these incremental increases in sea temperatures add up over time, providing ever-more fuel for storms high above the warming waves.

Did pollution reduce storms?

From the early 1940s through the mid-1960s, strong hurricanes hammered the Caribbean and North America. Then, a roughly three-decade breather settled in until the 1990s.

At first, scientists weren’t sure what was behind this diminished activity. Some pointed toward the Atlantic Multidecadal Oscillation, a natural temperature fluctuation in North Atlantic that happens every 25 to 40 years.

But then scientists found another clue: air pollution from Europe and North America.

Kerry Emanuel, a pioneering climate scientist from the Massachusetts Institute of Technology, and other teams studied how this constant haze of particles, or aerosols, drifted south and created enough cover to cool the Atlantic's hurricane nursery.

At the same time, this aerosol haze likely triggered droughts south of the Sahara. As these already dry areas grew drier, winds picked up enormous amounts of dust and carried them into the trade winds, further suppressing hurricane activity, Emanuel said.

But when European and North American nations cracked down on air polluters, especially power plants that burned coal, the cloud cover decreased. The sun beat down harder on the Atlantic's main development area, warming it.

“I’d argue that’s why we’re seeing more storms and stronger storms in the Atlantic than we were 40 years ago,” Emanuel said.

Yet higher temperatures in the Atlantic storm nursery can change the timing and paths of hurricanes in a potentially less destructive way, he added.

Tropical cyclones may get organized closer to Africa. This can give atmospheric steering currents from North America more time to push storms north into the open ocean and out of harm's way.

This happened in 2010. The tropical Atlantic was exceptionally warm that year, spawning one monster hurricane after another. All told, the storms carried nearly twice as much power as those during a typical hurricane season, scientists later calculated. But many formed on the African side of the main development region and cut north.

“They stayed out to sea,” Emanuel said. “So it didn’t really matter to most people, unless you were a captain of a ship.”

Weird 2024 hurricane season

The ocean is like a big battery, soaking up heat energy from the air. In early 2024, forecasters predicted the year’s Atlantic hurricane season would be much busier than average, in part because of all the stored energy in the main development region.

As if on cue, thunderstorms moved off the coast of West Africa on June 22. Moving east across the Atlantic hurricane nursery, the weather system spun into a tropical storm named Beryl. Beryl plowed into the Windward Islands as a Category 4 storm. In the Caribbean, it strengthened even more. For a time, Beryl packed sustained winds of 165 mph. It was the earliest Category 5 storm ever observed in the Atlantic.

Hurricane Debby followed in late July. It struck Florida and weakened into a tropical storm as it moved over South Carolina but still drenched parts with as much as 2 feet of rain.

In mid-August, Ernesto formed in the hurricane nursery and moved north in the mid-Atlantic, striking Bermuda.

And then the storm spigot shut off.

The African monsoons moved farther north than usual in late August, so far that even parts of the Sahara Desert saw record amounts of rain. Thunderstorms in these monsoon systems are often the seedlings that grow into tropical storms.

But the African jet's northerly twist sent these thunderstorms spinning off Morocco and Western Sahara, north of the main development region. In these cooler waters, the storms fell apart.

At the same time, dry air moved into the tropical Atlantic’s hurricane nursery.

The hurricane season suddenly was on hold.

The monsoons’ northerly move was baffling, said Gregory Jenkins, a climate scientist at Penn State who has worked extensively with researchers in West Africa.

And it highlights the need to gather more data about the climate in West Africa, he said. Doing so could help fine-tune global forecasting models, the computer-driven programs that help meteorologists make better predictions.

What’s clear is that the warming waters still contain plenty of energy to fuel hurricanes for the rest of the season.

“If the thunderstorms start rolling off West Africa and have good spin, then it's all back on."

Which is exactly what happened in mid-September, as one cluster of thunderstorms after another rolled off West Africa into the hurricane nursery. One of those clusters eventually floated into the Caribbean and seeded Hurricane Francine, which slammed into Louisiana Sept. 11. At the same time, the Atlantic's main development region boiled into activity, with one weather system spinning into a tropical depression.

Also clear is the havoc these warming seas are creating on both sides of the Atlantic.

In the Senegalese fishing community of Fass Boye, Jeuwriñ Diop said his 30-year-old son is now the one who goes out to sea in the family’s pirogue. On the boat, a flag for Barcelona, his favorite soccer team, flapped in the wind.

When asked whether he dreamed of migrating to Spain, Diop’s face betrayed the sensitivity of the topic, and he declined to answer directly. He said the air and water seem as if they carry more heat now. That weight has been absorbed by his community: by his relatives and friends who have left because the fish have gone, by those who died in the process.

“The sea,” he said, “is no longer what it used to be.”

About this story

Today’s story grew from “The Sahara Connection,” The Post and Courier’s deep dive last year into how dust from the Sahara affects our hurricanes.

Two Post and Courier journalists, Tony Bartelme and Andrew Whitaker, traveled to Senegal and Mauritania to document this phenomenon.

Working with Borso Tall, a Senegal journalist, they traveled to the dunes and talked with West African scientists who have done groundbreaking research into this important hurricane controller.

The stories showed how dust from the Sahara often creates a blanket over the open Atlantic’s main development region. This layer can smother storms as they spin off the African continent. When this dust clears, we often see a dramatic increase in the number of storms heading toward the Southeastern United States.

Both today’s report and the Sahara Connection were made possible with grants from the Pulitzer Center and The Post and Courier’s nonprofit Investigative Fund. The Pulitzer Center selected Tall for its Ocean Reporting Network fellowship, a yearlong program that focuses on ocean-related issues. She will collaborate with The Post and Courier on future stories that show the connectivity between West Africa and South Carolina.