The air around the Phoenix area was a hazy shade of brown and a layer of dirt coated cars and buildings Wednesday following a massive dust storm overnight.

The storm halted airline flights, knocked out power to nearly 10,000 people and fouled up thousands of swimming pools.

Because dust storms, also known by the Arabic term "haboobs," are so hard to predict, Tuesday's took everyone by surprise.

Seemingly out of nowhere, the storm moved like a giant wave, the dust roiling as it approached at up to 60 mph. Once it hit, visibility dropped to zero in some areas, the sky turned nearly black, trees blew sideways, and even downtown Phoenix skyscrapers became invisible.

"Just the height of it looked like a special-effect scene from a movie, like a dust storm out in Africa," said Charlotte Dewey, a National Weather Service meteorologist in Phoenix. "It looked so huge, looking at the city down below, it was just specks of light and miniature buildings.

"I have a feeling that people will be talking about this for another week or two, at least," Dewey said.

She said meteorologists were still trying to get exact measures from satellite and radar to figure out how big the dust storm was and compare it with previous ones, but they estimate it was more than a mile high and more than 100 miles wide. Initial reports had estimated it was 50 miles wide.

"People who've lived here their whole lives, 30 or 40 years, are saying they've never seen a storm this large," Dewey said.

She said winds from separate thunderstorms in the eastern and southern parts of the state collided somewhere between Phoenix and Tucson and combined with a severe lack of moisture to create the wall of dust. The storm also hit the Yuma area in southwestern Arizona, and far western Arizona.

Haboobs only happen in Arizona, the Sahara desert and parts of the Middle East because of dry conditions and large amounts of sand, Dewey said.

"It's a pretty rare thing to be able to see," she said.

While some Arizonans revel in the strange weather, many were unlucky enough to be outside when the storm rolled in. The storm blasted them with dust that went up their noses, behind their contact lenses and in their mouths, leaving behind a gritty taste.

Holly Ward, a spokeswoman at the Maricopa County Air Quality Department, said pollution levels skyrocketed.

During the storm, the amount of particulate matter in the air reached 375 micrograms per cubic meter, more than double the level federal standards consider healthy.
"You didn't have to go far anywhere in the dust storm to feel the remnants of that dust in your throat and in your nose," Ward said. "If someone already has breathing problems like asthma and bronchitis, this is an incredible health challenge and serious health threat for those folks."

The dust storm also grounded flights at Phoenix's Sky Harbor International Airport for 45 minutes. At least three flights were canceled and more than a dozen were delayed, while several incoming flights were diverted to Tucson and Ontario, Calif., said airport spokesman Julie Rodriguez.

Federal Aviation Administration spokesman Lynn Lunsford said planes need to be grounded during dust storms because of the low visibility, high winds and potential damage from the dirt.

"If you think about it, glass is made from sand that has been melted, and if you think about the temperature inside a jet engine, it's hot enough to melt sand," he said. "If you can't see through it, you definitely don't want to fly through it."

He likened the storm to volcanic ash that wreaked havoc in the skies in April 2010, when an eruption grounded flights across Europe for days, disrupting travel for 10 million people.

The Arizona Republic reported winds also downed live wires in Tempe that sparked a fire at a busy intersection. Firefighters later extinguished the blaze.
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