Cape Verde Hurricanes Are Rarely A US Threat | Weather.com (2024)

C​ape Verde hurricanes are some of the Atlantic's strongest, but they usually don't make it to the mainland. Those more "homegrown" are more often a U.S. threat.

Origin of "Cape Verde": Each hurricane season, meteorologists focus on weather disturbances known as tropical waves that march westward off the coast of Africa into the Atlantic Ocean. According to the National Hurricane Center, about 85% of major hurricanes and about 60% of other tropical storms and hurricanes develop from these disturbances.

These tropical waves sometimes waste little time strengthening into a tropical storm and then a hurricane after moving off Africa.

These early developers are called "Cape Verde hurricanes," named for the group of islands near which they often first become tropical storms, now known as the Republic of Cabo Verde.

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When and how often: Cape Verde hurricanes usually happen in August or September. That's when the eastern Atlantic Ocean, not to mention much of the tropical Atlantic Basin, is most favorable for development.

But there aren't usually many Cape Verde hurricanes. Some hurricane seasons may have as many as five. Many other years fail to produce a single one.

Examples: The most recent Cape Verde hurricanes were in 2021, when both Larry and Sam intensified quickly between Africa and the Lesser Antilles.

Another recent example was 2019's Hurricane Lorenzo. Lorenzo not only developed south of the Republic of Cabo Verde, but also exploded into the strongest hurricane on record in the eastern Atlantic Ocean.

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How often a U.S. threat: Weather.com analyzed 224 hurricane tracks from 1995 through 2023 to calculate how much of a threat to the U.S. these Cape Verde hurricanes have been.

We picked that time frame because hurricane seasons have mostly been more active since 1995 than in, say, the 1970s and 1980s.

Our analysis revealed these hurricanes don't often reach the mainland U.S., but when they do, they tend to be destructive.

Of those 224 hurricanes, 55 either made landfall or brushed very close to the mainland U.S. to produce some direct impacts. That's an average of about two U.S. hurricanes per season since the mid-1990s.

But only eight out of 55 hurricanes that reached the U.S. were of the Cape Verde variety.

Why so few U.S. Cape Verde hurricanes: Cape Verde hurricanes have thousands of miles of ocean to cover to make it to the U.S. A lot of things often go wrong along the way.

They can be carried farther north into the central Atlantic Ocean if the Bermuda-Azores high is weaker or less expansive than normal. These recurving storms then curl around the weaker high well off the U.S. East Coast.

Surges of hot air from the Sahara Desert known as Saharan Air Layers move off the African coast every three to five days from late spring through early fall.

Wind shear is another factor that doesn't allow development in the eastern Atlantic Ocean early in the season. These differing winds with height can rip apart a system trying to become a tropical storm.

The few that made it: While Cape Verde hurricanes are few and make up a small fraction of U.S. hurricane landfalls, those that have made the entire voyage were almost always very destructive.

September 2018's Hurricane Florence was the last Cape Verde hurricane to hit the U.S. Despite weakening winds before landfall, its slow crawl over the Carolinas triggered catastrophic flooding.

Others included Irma (2017), Ike (2008), Ivan (2004), Frances (2004), Isabel (2003), Georges (1998) and Bertha (1996).

All but one of these – Bertha in 1996 – were so damaging that their names were retired from future use.

In these cases, there was not enough dry air or wind shear to put a lid on their intensification, and expansive, strong high pressure to their north ensured they would be steered to the U.S.

Bigger U​.S. threat is "homegrown": Much more often, a U.S. hurricane threat usually comes from storms that develop much closer.

As the map below shows, of the 55 U.S.-impacting hurricanes from 1995 through 2023, only 10 first became hurricanes between the Lesser Antilles and Africa.

The large majority of them first became hurricanes in the Caribbean Sea, Gulf of Mexico or near the Southeast coast.

One reason for this is simple geography. The closer to the U.S. it becomes a hurricane, the better chance of a U.S. hurricane landfall. A Gulf of Mexico hurricane has nowhere else to go except Mexico or the U.S. if it doesn't fizzle first.

But sometimes, the tropical wave encounters a hostile environment of dry air and wind shear elsewhere in the Atlantic, only to find a much more hospitable environment closer to the U.S.

Deep, warm water is typically most plentiful in the Caribbean Sea and Gulf of Mexico, so development in this part of the tropics isn't simply limited to August and September.

Every hurricane should be taken seriously, particularly those in the Caribbean Sea, Gulf of Mexico, or off the Southeast coast.

But much more often than not, Cape Verde hurricanes – even stronger ones – have to clear some atmospheric hurdles before they become a U.S. threat.

M​ORE ON WEATHER.COM

-​ How Long It Takes Hurricanes To Reach The US

-​ September Is Hurricane Season's Busiest Month

-​ Hurricanes Can Form In Many Ways

Jonathan Erdman is a senior meteorologist at weather.com and has been covering national and international weather since 1996. His lifelong love of meteorology began with a close encounter with a tornado as a child in Wisconsin. Extreme and bizarre weather are his favorite topics. Reach out to him on X (formerly Twitter), Threads, Facebook and Bluesky.