The Black Sunday storm of April 14, 1935, was a haboob, as were most of the storms that ravaged the Dust Bowl in the 1930s. Haboobs are often called "black blizzards" or "black wind storms." They can span 60 to 90 miles (96 to 145 kilometers) in length and reach heights of 5,000 to 8,000 feet (1.5 to 2.4 kilometers), although haboobs have been known to tower as high as 15,000 feet (4.5 kilometers).
Haboobs are the temper-tantrum-prone siblings in the dust storm family. They're relatively small compared to the massive storms that are caused by synoptic-scale systems, but they tend to erupt out of nowhere and with dramatic fanfare. They're common in the Sudan and North America, namely the Southwest plains. As we just found out, they're associated with thunderstorm activity. But what does a thunderstorm, which we usually associate with rain, have to do with a dust storm? Well, the connective winds that typically associate with thunderstorm activity play a big role in generating a dust storm. Many times, rain will follow a haboob, but it's often unnoticed as the actual rainfall is usually insignificant.
When thunderstorms dissipate, gust fronts, or outflow boundaries, are formed as downdrafts hit the ground and spread out from the storm, where it begins to rain. These gust fronts, which can exceed 50 miles per hour (80.5 kilometers per hour), act as "mini-cold fronts" racing out from the dissipating storm. When the gust fronts sweep across exposed dry land, dust is kicked up into the air similar to the larger scale fronts described above, only with more intensity. True to fashion of your typical three-year old, the resulting tantrum is quite a show; the airborne dust forms into a towering, condensed thick wall, moving with the storm at about one half the speed of the gust front, typically 30 miles per hour (48 kilometers per hour) [source: University Corporation for Atmospheric Research]. However, similar to temper tantrums, these storms don't last very long. Haboobs tend to be over within three hours and visibility improves shortly after the winds subside.
The effects of haboobs are similar to most major dust storms, but they're a bit more chaotic due to the rapid formation and intensity of the convective winds that are responsible for the storm. Strong winds blowing dust around decrease visibility and deposit sediment everywhere, which seriously jams electrical equipment, machinery and even helicopters. Power lines are often blown down and air travel comes to a halt. The whipping dust, which feels like fine sand, can cause respiratory problems, especially for people with asthma.
The most immediate dangers during a haboob are aircraft collisions and highway accidents. Visibility can be reduced to near zero in a matter of two minutes during a haboob -- if you happen to be motoring down the highway, this can be life-threatening. Pile-up collisions are a common occurrence during black blizzards.
While it's likely you'll survive a dust storm, there can be long-term consequences once the dust settles. In the next section, we'll examine how dust storms can affect our health and communities.