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Yahoo
2 days ago
- Climate
- Yahoo
A Saharan dust cloud is headed to the U.S.: How does this occur?
After making its way across the Atlantic Ocean, a massive cloud of dust from the Sahara Desert is expected to reach the U.S. on Wednesday afternoon. The cloud of dust, which is believed to stretch 2,000 miles west to east and 750 miles from north to south, will first hit Florida and then spread to other states, according to USA Today. When it reaches Florida it will have traveled over 5,000 miles from North Africa. This is the largest Saharan dust cloud so far this year to travel across the Atlantic. It is expected to have little effect on air quality, as it will remain high in the atmosphere, but Floridians should see hazy skies or colorful sunrises and sunsets midweek. 'Typically we have nice blue skies, but with the dust, the whole sky looks soft and warm because the particles themselves are red,' said Joseph Prospero, professor emeritus at the University of Miami Center for Aerosol Science and Technology, according to The New York Times. 'Everything looks muted,' he added. This dust is technically known as the Saharan Air Layer, or SAL, and is a relatively common feature, according to The Washington Post. It is more unusual to see the SAL stay so strong after journeying across the ocean. The SAL is a very dry and dusty mass of air that forms above the Sahara Desert in late spring, summer and early fall, according to the Atlantic Oceanographic and Meteorological Laboratory. Every few days the dust clouds move over the Atlantic Ocean. According to The New York Times, the dry layer of air that makes up the SAL hovers around a mile above the Earth's surface and can be up to 2.5 miles deep. The SAL is carried west by the same winds that kick up hurricane season. These dust events can happen year-round but the largest occur from mid-June to late July and after early August the plumes of dust tend not to travel as far. Earlier this year a few smaller SALs crossed the ocean but this is the first significant plume of the year. 'It happens every year; some years have more dust transportation across the Atlantic than others,' said Sammy Hadi, a meteorologist at the National Weather Service office in Miami, per The New York Times. 'It's like rinse and repeat every year, it's part of a normal cycle of Earth's oscillations.' Since the SAL is brought on by the same winds that drive tropical disturbances, excessive levels of dust can suppress and stifle tropical storms. This happens because the dust clouds are so dry and tropical storms require moisture to grow, per The Washington Post. The dust cloud is formed by light dry sands and other minerals, but they require a jet stream positioned correctly to send them westward. The SAL can also be shot northward toward Europe. This particular cloud that will reach the U.S. stirred up over Africa near Chad in late May. Meteorologists get plenty of notice for when an SAL is headed to the U.S., since the dust storms are visible by satellite developing over the Sahara seven to 10 days before reaching the Caribbean or the Gulf of Mexico, per The New York Times. Earlier this week, the dust cloud covered the Caribbean islands on its way to the U.S. The cloud was dense and caused hazy skies in Puerto Rico, and early Wednesday morning the cloud was affecting Cuba, per USA Today. The plume of dust should reach south Florida by Wednesday afternoon or evening, and then on Thursday it is expected to spread to the rest of Florida going north into parts of Georgia and South Carolina. By the weekend, it is predicted to reach other Gulf Coast and Southeastern states such as Louisiana, Mississippi and Alabama, reported AccuWeather. It is then expected to dissipate. Jason Dunion, a meteorologist who monitors Saharan dust and hurricanes, has been in Puerto Rico during a Saharan dust event before, per The New York Times. 'There's a lot of dry air, and you don't feel that dry air, but the clouds feel it because as they grow and form thunderstorms, they run into that dry air and they just collapse,' he said. 'They get stifled. So as this comes through to a place like Puerto Rico, you're going to tend to have fewer thunderstorms. It's going to probably be one of our hotter days. And very hazy. The haze is incredible.' It is possible that the Saharan dust could collide with smoke which made its way to the U.S. from wildfires burning in Canada, per USA Today. The smoke has caused unhealthy air quality in several states over the last week, including Minnesota and Wisconsin. It has also caused moderate air quality across most of the eastern half of the country. Later in the week, there could be a small area where the smoke and dust come together over the southeast, per USA Today. It should not cause health or safety issues, except for sensitive groups.
Daily Mail
4 days ago
- Climate
- Daily Mail
Massive plume of dust barrels toward Florida
A massive plume of dust the size of the entire US is moving across the Atlantic Ocean and is set to hit Florida this week. The dust cloud is coming from the Sahara Desert and was formed by strong winds sweeping tiny sand and mineral particles off the surface. The plume is predicted to hit South Florida by Wednesday and the Gulf States a few days later, but locals could begin seeing dust hanging in the atmosphere sooner. Experts warn that it can make breathing difficult, especially for people with asthma, allergies, or other respiratory issues, because it carries fine particles that can irritate the lungs. As of Monday, t he cloud extended roughly 2,000 miles from Jamaica to well past Barbados in the eastern Caribbean, and about 750 miles from the Turks and Caicos Islands in the north down to Trinidad and Tobago in the south. 'It's very impressive,' said Alex DaSilva, lead hurricane expert with AccuWeather. While the plume is moving toward the US, DaSilva said it likely lost most of its concentration in the eastern Caribbean. 'Those islands tend to see more of an impact, more of a concentration where it can actually block out the sun a little bit at times,' he added. Scientists in Florida have reported seeing slightly hazy skies. Pictured: A general view of San Salvador as dust carried by winds from the Sahara desert shrouds city, in El Salvador June 25, 2020. Joseph Prospero, professor emeritus at the University of Miami Center for Aerosol Science and Technology, told The New York Times: 'Typically we have nice blue skies, but with the dust, the whole sky looks soft and warm because the particles themselves are red.' 'Everything looks muted,' he added. The dry and dusty air known as the Saharan Air Layer forms over the Sahara Desert in Africa and moves west across the Atlantic Ocean starting around April until about October. Each summer, seasonal weather patterns like the West African Monsoon and high-pressure systems create strong winds that sweep across the Sahara. These winds pick up tiny particles known as aeolian dust and lift them into the atmosphere. Meanwhile, the Bermuda-Azores High, a high-pressure system over the Atlantic Ocean, produces steady east-to-west winds that help carry the dust across the ocean. It also prevents tropical waves from forming during the Atlantic hurricane season, which runs June 1 to November 30. June and July usually have the highest dust concentration on average, with plumes traveling anywhere from 5,000 feet to 20,000 feet above the ground, DaSilva said. In June 2020, a massive Saharan dust cloud, nicknamed the 'Godzilla plume,' swept from West Africa across the Atlantic, bringing hazy skies from Texas to the Carolinas. The National Oceanic and Atmospheric Administration (NOAA) called it the largest event in nearly 50 years, with reduced visibility and air quality alerts issued across multiple states. Then in July 2023, another thick wave of Saharan dust blanketed Florida, Texas, Louisiana, Alabama, and Mississippi, turning skies orange and pushing air quality into 'unhealthy for sensitive groups' in cities like Miami and Houston. This year's plume is different as it's earlier, denser, and more concentrated, with higher levels of fine particles. As a result, health officials and meteorologists are keeping a close eye on its impact. The size and intensity of these dust clouds vary from year to year, but scientists believe that shifting wind patterns and climate change may be contributing to more frequent and powerful plumes.
New York Times
5 days ago
- Climate
- New York Times
A Giant Plume of Saharan Dust Is Headed to Florida
A giant cloud of Saharan dust the size of the continental United States floating over the Atlantic Ocean was expected to spread across the Gulf Coast region this week. By the time the thick plume reaches Florida, it will have traveled over 5,000 miles from North Africa. The National Weather Service office in Puerto Rico warned of poor air quality and advised people with respiratory issues such as asthma to wear masks. The plume will have lost some density by the time it reaches South Florida and other Gulf Coast states by the middle of the week, but residents may still notice that the world outside appears different as dust high in the atmosphere scatters sunlight. 'Typically we have nice blue skies, but with the dust, the whole sky looks soft and warm because the particles themselves are red,' said Joseph Prospero, professor emeritus at the University of Miami Center for Aerosol Science and Technology. 'Everything looks muted,' he said. Dust plume season is just beginning. The transport of dust from the Sahara in North Africa to far-flung places across the globe is one of the great wonders of the weather world. And we're right at the start of the season when dust most commonly moves across the Atlantic. The dust headed toward the United States left Africa last week and drifted into the Caribbean over the weekend. Want all of The Times? Subscribe.
