True grit: Understanding dust storms

Dust storms are happening more frequently across the United States. Here’s what you should know.

In the United States, the number of dust storms, also known as haboobs (Arabic for “strong wind”), is on the rise. In the 1990s, scientists reported 20 dust storms per year; that number has more than doubled, to 48 per year in the 2000s. The southwestern United States, especially, has seen a large rise in the number of storms. Dust storms provide a number of unique hazards for aircraft.

Encountering Dust Storms

While most common in desert areas, dust storms can be encountered when flying over any large area of land comprised mostly of dry soil. These storms are created when strong winds suspend dust into the air and keep it suspended. When the atmosphere is unstable, vertical mixing can occur and send the dust storm as high as 15,000 ft. Typically, dust storms last anywhere from a few minutes to an hour before clearing.

Dust Storm Hazards

Dust storms create several hazards for both small and large aircraft alike since they often appear quickly and without warning. Clear skies can be filled with churning dust in just a matter of minutes. As a result, visibility can be dramatically reduced or even result in inadvertent instrument meteorological conditions (IIMC).

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The rising dust is not the only threat, however. The strong winds responsible for creating the dust storm can also be a hazard to pilots. Wind gusts of 25 mph or more are usually associated with dust storms. These winds can change quickly and unexpectedly. High, unpredictable winds can cause difficulty for pilots during takeoff and landing, and may increase the chance for turbulence while en route.

Dust storms may also pose a hazard to the aircraft itself. If dust particles make their way into an engine it can damage air intakes, electro-optical systems, or affect the fan or propeller blades, ultimately resulting in decreased engine performance. Additionally, blowing dust can damage the external surface of the aircraft.

Ground operations at airport terminals may also be affected by dust storms. Outside workers may be hampered or even prevented from doing their jobs by blowing dust, strong winds, and limited visibility. The dust itself may also pose health hazards to ground personnel and pilots if it is breathed in. Strong storms can leave dust on runways, and must be cleaned up before normal operations can be resumed.

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NWS Dust/Sandstorm Reporting

Dust storms are difficult to forecast, and the U.S. National Weather Service typically waits until after a dust storm has formed to issue either an “advisory” or “warning” related to the dust storm; SIGMETs may also be issued for widespread dust storms or sandstorms that reduce visibility. The grid below illustrates the criteria for issuing these advisements:

Blowing Dust Advisory Dust Storm Warning SIGMET
Visibility ¼ mi (0.4 km) – 1 mi Below ¼ mi (0.4 km)  
Wind Speed 25 mph (40 kph) or greater 25 mph (40) kph or greater n/a

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