Arizonans are calling it the mother of all haboobs _ a mile-high wall of ominous, billowing dust that appeared to swallow Phoenix and its suburbs.
The massive dust storm, also called a "haboob" in Arabic and around Arizona, is all locals could talk about Wednesday. It moved through the state around sundown Tuesday, halting airline flights, knocking out power to nearly 10,000 people, turning swimming pools into mud pits and caking cars with dirt.
The sky was still filled with a hazy shade of brown a day later as residents washed their cars and swept sidewalks.
Because haboobs are so hard to predict, Tuesday's took everyone by surprise.
Seemingly out of nowhere, the 100-mile-wide 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.
"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. They got blasted 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. Particulate matter at one monitoring site hit an hourly average of more than 5,000 micrograms per cubic meter. Tuesday's 24-hour average was as high as 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."
Local hospitals were expecting an increase in a disease known as Valley Fever, a fungal pneumonia, because of the storm. The fungus thrives in the hot and arid Southwest and is found just a few feet beneath the earth's surface; it can be stirred up by construction, wind and other activity.
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.
Arizona's dust storm annoyed others who couldn't see out of their car windows or found their pools filthy in the morning. But that created pay dirt at local businesses.
"It's crazy here," said Margaret Viloria, manager of Los Olivos Hand Car Wash near downtown Phoenix. "When we opened this morning cars were lined up outside. It's just been nonstop."
On a typical day, the car wash cleans about 25 to 30 cars an hour. It was averaging 55 an hour Wednesday, Viloria said.
Joe Pinelli, owner of The Pool Service in Phoenix, was also having an "absolutely chaotic" day.
"I don't think I've been off the phone since about 6 a.m.," he said.
Dewey, the weather service meteorologist, said there was a slight chance of blowing dust in the Phoenix area Wednesday and Thursday and a slight chance of thunderstorms the rest of the week.
"As far as if it would be of any magnitude we saw Tuesday, I don't know," she said.
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