“Apocalyptic” might as well have been the forecast for Lubbock, Texas, on June 5, 2019.

Around 6 p.m. that day, the local National Weather Service warned of an inbound rush of dust-laden, 60-mile-per-hour winds and severe thunderstorm, altogether deemed an “extremely dangerous situation.” Within an hour, Lubbock residents received their first dust storm warning in five years and the motorists among them were advised: “Pull aside, stay alive.” A haboob—an enormous, storm-born front of dust—was on its way.

Matthew Cappucci, a meteorologist for The Washington Post, found himself face-to-face with the haboob. “Within seconds, it was on me,” Cappucci describes. “I was sandblasted, grains still lodged in my eyes, nose, and ears 18 hours later. I returned to the refuge of my vehicle as 60 to 70 mph winds buffeted what seconds before had been a tranquil, picturesque scene.” Cappucci goes on to recount a slurry of hazards during and after the haboob: flooding, blinding rain, pebbles of hail, and “additional waves of dusty rain (that) deposited a thin veil of grit on my freshly washed truck.”

So what causes these insane blasts of dusty catastrophe? Named after the Arabic word habb, meaning “to blow,” haboobs occur when strong winds sweep up dust, dirt, or other fine particles of earth and loft them into a wall-like front that can be many miles long, up to 5,000 feet tall, and last for minutes to hours. Along the fringes of that front, intense wind and dust whirls or devils can herald the arrival of a haboob, according to the National Audubon’s Field Guide to Weather.

Despite their dangerous nature, these bizarre events can conjure beautiful imagery. Even the American Meteorological Society can’t help but describe haboobs as “visually stunning.” They resemble a brown avalanche (and are sometimes called black blizzards) that can blacken daylight and even be visible from space, in the case of haboobs in North African and Arabian deserts, writes author Cynthia Barnett in Rain: A Natural and Cultural History.

The term originated as a description for the windy sandstorms in central and northern Sudan, especially around Khartoum—which experiences, on average, 24 haboobs annually, according to the American Meteorological Society. But they’re a worldwide phenomenon spanning arid or semiarid regions from the Middle East to the Sahara Desert, central Australia, and Mexico’s Sonoran Desert.

In the United States, they’re most common during thunderstorms in arid areas such as the Southwest, says University of Oklahoma meteorologist Jason Furtado. Though both involve gusts of dust, the terms ‘haboob’ and ‘sandstorm’ can’t be used interchangeably, he says. “Every haboob is a sand storm, but not every sandstorm is a haboob,” Furtado says, since haboobs by definition are the byproduct of a thunderstorm, whereas sand or dust storms can happen anytime strong winds pick up particles.

Raindrops evaporate when they fall into very dry air, Furtado explains, which causes the air to turn cold and dense—and plummet. That dropping mass of cold air eventually hits the ground, and, like a book dropping onto a dusty tabletop, creates an outward gust that can pick up and carry particles. “If that hits in a dusty, dry area, really intense winds form and move a big wall of dust,” Furtado says.

Broadly speaking, however, humans have experienced sun-occluding sand and dust storms for centuries. “Chinese records speak of sandstorms occurring around A.D. 960, when a yellow dust covered the sky and laid waste to the fields,” writes Leslie Alan Horvitz in The Essential Book of Weather Lore. Modern humans have also witnessed some awe-worthy sandstorms.

In 2000, for example, dust storms carried some 8 million tons of Saharan sand as far west as Puerto Rico. This January, dust storms and 60-mile-per-hour winds swept across eastern Australia. “It was so thick we couldn’t see across the road,” a motel manager told The Daily Telegraph.

The sudden shift in air quality that these weather events create also makes them a hazard to human health, particularly those with underlying conditions. Public health officials often warn of the potential hazards associated with haboobs, and instruct people with respiratory and cardiovascular conditions such as asthma, chronic bronchitis, emphysema, or heart disease to reduce or avoid strenuous outdoor activities. Even still, being inside doesn’t totally protect someone from dust storms, which have been known to penetrate window frames or small cracks in houses and cause respiratory distress in humans and animals, according to the National Audubon’s field guide.

We often under-appreciate the air quality impact of these dust storms, says Ryan Stauffer, a research scientist at the University of Maryland and NASA’s Goddard Space Flight Center. Though the particles of soil or sand themselves are often naturally occurring, he says, their fine size, of 10 micrometers or less, qualifies them as a pollutant. “That’s small enough that it can get deep in your lungs and cause respiratory issues,” Stauffer says. “The stuff can be quite hazardous actually.”

Researchers have explored other health risks posed by haboobs and dust storms. In the 1930s, thousands died from “dust pneumonia” caused by epic Dust Bowl-era storms, which are also believed to have helped spread measles and other infectious diseases. In 2014, scientists from Arizona, Egypt, and Serbia explored whether a haboob in Phoenix some years earlier had spread soil-dwelling fungi that causes valley fever to highly populated areas. Valley fever can be fatal in extreme cases but more often means months of shortness of breath, exhaustion, and skin rashes.

More frequent, dangerous heat waves fueled by climate change don’t mix well with sandstorms like haboobs, Furtado says. Grit from haboobs can infiltrate air conditioning vents and cut off access to indoor cooling during the hottest parts of the year. “It can be a big deal,” he says.

These massive dust storms can also destroy the physical landscape by uprooting trees, tumbling power lines, and damaging buildings and homes.

They can also jeopardize the aviation industry in a variety of ways. Scattered sand particles can clog air filtration systems and dull the blades of propellers and turbine engines. In 2011, a mile-high tall, 100-mile-long haboob delayed flights in and out of Arizona’s largest airport, where dust also set off smoke alarms (seven years later, another mile-high haboob in the Phoenix region shut down the Sky Harbor International Airport). Sandstorms also dangerously impair visibility for drivers and pilots. For example, reports from the 1980 Iranian hostage rescue mission “included references to in-flight encounters with haboobs which may have played a direct role” in a Navy helicopter colliding with a C-130 aircraft while dust conditions were heavy.

Haboobs are likely to become a more commonplace global phenomenon due to anthropogenic forces such as overgrazing, deforestation, and depletion of water resources in densely populated arid regions, writes Horvitz. Intense droughts—which are expected to increase as climate change intensifies—exacerbate the problem, Stauffer and other experts say. Last August, the Intergovernmental Panel on Climate Change predicted this vicious cycle: Ongoing soil degradation will hasten desertification. As some areas get hotter and drier, reserves of water in the soil evaporate—which means there’s less humidity available to form clouds to cool and moisten the landscape. “It keeps cycling down that path, getting drier and drier,” Furtado says. “It just spirals down.”

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