Saharan dust helps keep hurricanes at bay, but has other less-appealing effects

MIAMI – It is not only hot in South Florida, but it’s also hazy.

Saharan dust is to blame for that, and while it keeps the tropics at bay, it can also be harmful to our health, especially for those suffering from respiratory conditions.

“They start coming off in June and we’re at the peak right now, so it’s pretty normal and every three to five days or so we’ll see a new outbreak coming across the Atlantic from Africa,” said Jason P. Dunion, a hurricane researcher with the University of Miami. “We call it the Saharan air layer and the plumes are huge. About the size of the lower 48 states when they come across.”

When plumes of Saharan dust drift across the Atlantic Ocean to South Florida, it’s what can generate beautiful sunrises and sunsets.

“The dust is a very good forward scatter,” said Dunion. “So light that’s coming at the viewers hits that dust and gets scattered in all directions.”

The dust can also inhibit the formation of thunderstorms that fuel hurricanes.

“It can be beautiful -- there’s also very strong winds that can rip the clouds apart,” said Dunion. “It is very dry about a mile above your head -- about half the moisture you’d expect to see in the tropics -- but it’s way up there. Dust that absorbs the sun and makes it warm, working against cloud formation, all these things can work against cloud formation and even hurricanes, so it is kind of the worst of both worlds.

“As far as South Florida weather goes, you have still very soupy and hot at the surface and you don’t get those nice thunderstorms in the afternoon that tend to form in places like the Everglades that could cool off the afternoon temperatures.”

Additionally, Saharan dust can also create an air quality health risk, especially for those who suffer from asthma and allergies.

Dunion said later this week he will be traveling to Barbados to continue his study of how the dust and dry air impact hurricane formation. He added that the dust outbreaks begin to ramp down around mid-August.


About the Author

Christina returned to Local 10 in 2019 as a reporter after covering Hurricane Dorian for the station. She is an Edward R. Murrow Award-winning journalist and previously earned an Emmy Award while at WPLG for her investigative consumer protection segment "Call Christina."

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