'Haboob' causes blackouts and flight cancellations in parts of Arizona: What are these giant dust walls?

File image of a 'Haboob' advancing over palm groves in Dongola in Sudan's Northern State on August 30, 2024. (Image used for representation)

On Monday evening, parts of central Arizona were swallowed by a towering wall of dust that stunned residents and briefly brought daily life to a halt.

These dramatic events, known as haboobs, form when thunderstorms unleash powerful winds that lift massive amounts of dust and debris into the sky. According to the US National Weather Service (NWS), such dust walls can rise thousands of feet, stretch for miles, and sweep across landscapes with little warning.

The storm in Arizona dropped visibility to just a quarter-mile in some areas. The state’s Department of Transportation urged drivers to stay off the roads, while flights at Phoenix Sky Harbor International Airport were suspended for a short period. More than 40,000 customers in Maricopa County lost power, The New York Times reported.

Although striking images of haboobs often circulate widely online, these storms are not unusual. The US National Oceanic and Atmospheric Administration (NOAA) says the Phoenix area typically experiences one to three large dust storms each year.

How do Haboobs form?

The phenomenon starts with thunderstorms that produce powerful downdrafts.

“Thunderstorms can produce strong downdrafts that hit the ground at 50-80 mph (80-129 kph) and then spread in all directions,” said Sean Benedict, a meteorologist at the National Weather Service’s Phoenix office.

These winds sweep up loose dust from deserts, dry riverbeds, and farmland, driving it forward along the leading edge of the storm cell.

If thunderstorms fade, the dust quickly settles. But in some cases, rain-cooled air ahead of a storm can lift warm air upward, fueling more storm development and more downdrafts.

“When that happens, the haboob can keep growing, and some travel as far as 100 miles (161 kilometres),” Benedict said.

Whether a haboob forms and grows depends on local geography and land use. “It’s all dependent on whether they’re moving through an area that’s prone to (generating) dust,” Benedict added, noting the prominent dust corridor between Phoenix and Tucson.

Haboobs are also known to form in other dry regions such as Nevada, New Mexico, and Texas.

Will they become more common?

Scientists studying the US Southwest say that climate change could be influencing the conditions that make haboobs possible.

Since the 1970s, bursts of rain during the summer monsoon season have become more intense as the atmosphere warms, while rainfall overall has become less frequent. Longer droughts and expanding arid regions mean more exposed land where dust can be picked up.

This combination raises the likelihood of severe storms and stronger dust events. Still, experts are cautious.

Benedict explained that it is hard to say whether haboobs will increase in frequency because they depend on very specific circumstances. Land use, such as farming practices, also plays a role in how much dust is available to be lifted into the air.

It is worth noting that not all dust storms are haboobs. Only those linked to thunderstorm downdrafts fall into this category.

Staying safe in a Haboob

The NWS issues dust warnings when it expects thunderstorms and high winds in areas prone to dust. Such warnings are critical for drivers, as visibility can plummet to near zero in a matter of seconds.

That was the case in Arizona this week, when sudden walls of dust turned familiar cityscapes into near-total darkness, reminding residents that these storms are as dangerous as they are awe-inspiring.