What Is a Haboob? An Overview of Weather's Colossal Dust Storms

Haboobs may have a peculiar name, but these apocalyptic-looking sandstorms are nothing to sneeze at. Originating from the Arabic word habb meaning "to blow," these weather phenomena fill the skies when thunderstorm-induced winds kick up loose sand and dirt from the ground, resulting in a billowing wall of dust and debris.

Although the first haboobs were observed in Sudan, Africa, similar storms also occur in the Middle East, Central Australia, the American Southwest (most notably in Arizona and Texas), and even on Mars.

How Haboobs Form

Sand and dust storms typically occur in deserts and other dry regions when strong winds lift loose, dry soils airborne. In the case of haboobs, these winds originate from the outflow winds, or "gust fronts," of thunderstorms. 

Outflow winds are related to downdrafts—the columns of sinking air that form within thunderstorms when rain and hail become too heavy for the updraft (the warm, moist air flowing into the storm) to keep suspended. As air within a downdraft sinks, it cools, rushes toward the ground, then spreads out in all directions, like a ripple in a pond. This pool of cool, radiating air is the outflow. It can travel dozens of miles outward from its parent thunderstorm. It also acts as a mini cold front, complete with cooler temperatures and gusty winds. 

If outflow winds travel over large expanses of desert, they'll kick up lots of dirt and dust, thereby creating haboobs. According to the National Oceanic and Atmospheric Administration (NOAA), haboobs typically lift sand and dust as high as 10,000 feet into the air. These massive storms can also travel at speeds of 60 miles per hour, measure up to 100 miles wide, and last for 10 to 30 minutes, or longer.

Tracking and Forecasting Dust Storms

Meteorologists are able to detect the leading edge of an outflow, and thus haboobs, by using a tool that's generally associated with tracking rain and snow: Doppler weather radar.

On radar, outflow boundaries appear as blue, bow-shaped signatures moving in the same direction as a thunderstorm cell, but some distance out ahead of it. Not every outflow is associated with dust storm activity, but if "ground clutter" (what appears to be light precipitation where no precipitation is actually occurring) appears alongside the gust front, it's a good indication that dust is indeed being stirred up by outflow winds.

When it comes to spotting haboobs, radar does have its limitations though; it can't be used to detect how much dust a particular storm carries.

If forecasters are aware that conditions are favorable for haboobs (for example, if an outflow boundary is spotted in the midst of an ongoing drought), NOAA's National Weather Service may preemptively issue a dust storm watch. Whenever visibility reduces to one-half a mile or less due to blowing dust or sand and winds of 30 mph or more, the alert gets upgraded to a dust storm warning. However, even when weather alerts are issued, the swift speed of dust storms means they often appear quickly, catching people unaware.

How Hazardous Are Haboobs?

Not only are haboobs unnerving to witness, they can be deadly, too. Airborne dust can reduce visibility to near zero in mere seconds, leading to vehicle accidents on roadways. Dust can also remain suspended in the air for days, triggering code orange air quality and allergy outbreaks for those with respiratory sensitivities.

The Arizona Emergency Information Network recommends that motorists who encounter haboobs pull off of the road, turn off their headlights and taillights, put their car in park, and wait for the storm to pass.

Dust In a Warming World

The connection between climate change and dust storms is still being studied, however, one thing is clear: The dynamics of dust are shifting as climate, namely warming air temperatures, does.

As you might have guessed, one of the biggest ways climate change impacts dust patterns is by increasing drought. As the climate warms, evaporation increases, which leads to more moisture being sucked out of ground soils and transported into the atmosphere as water vapor. This, in turn, causes soils to dry, and vegetation, whose root systems help to anchor the soil in place, to die off.

And without anything to keep them grounded, soils are free to become airborne. According to an NOAA-led research study, the frequency of dust storms in the southwestern U.S. has more than doubled, rising from about 20 per year in the 1990s to nearly 50 per year in the 2000s.