ARIZONA

Arizona Then and Now: Dust storms

Towering walls of dust look dramatic, can wreak havoc.

Weldon B. Johnson, The Republic | azcentral.com

It looked like a scene in a science-fiction movie: a towering wall of dust approaching Phoenix and seeming to swallow up everything in its path.

Dust covers Interstate 10 at mile marker 152 on Feb. 22, 1977.

On July 5, 2011, that scene was real. The world gaped at one of the more spectacular examples of something Valley residents regard as a typical part of summer.

Giant walls of dust, also known as haboobs, often blow through the Valley during the summer months. These dramatic dust clouds are caused by the outflow winds from strong thunderstorms outside the Valley. Most often, they are driven by storms south of the city but they can come from any direction.

Not all reach the dramatic scale of the July 2011 haboob, which was estimated to have reached heights of over 6,000 feet. The largest dust clouds usually occur early in the summer when the soil has been undisturbed for weeks.

Blowing dust on a smaller scale, narrow channels of the stuff caused by wind, can be even more destructive than large clouds if they cross highways. Those narrow dust channels are harder to detect and can occur without warning.

Many of the pileups along Interstate 10  south of Phoenix are caused by these narrow channels of blowing dust.

Such was the case on Oct. 29, 2013. A dust channel blew across I-10, contributing to 19-car pileup that caused three deaths near Picacho Peak.

The National Weather Service's Phoenix office is working to develop sensors that will help detect small dust channels and provide a chance to warn the public of potential dangers.