Arizona Dust Storm Report Released Online by National Weather Service; Dissects Cause and Development

The July 5 dust storm was among the most "significant" ever seen by National Weather Service experts who have been in the Valley 30 years, according to a new online report.

Everything you wanted to know about the meteorology of the storm that sand-blasted the Valley on Tuesday is contained in the NWS' report published today on the Web, (tip of the hat to Scottsdale newshound Pete Kosednar, who told us about it).

The "very large and historic" dust storm began with thunderstorms that developed east of Tucson on Tuesday, the report says. The monsoon-season weather produced downdrafts of up to 70 mph, which helped whipped up all that beige powder.

Although the height of the ensuing dust cloud that began heading toward the southeast Valley was up to 6,000 feet high, Doppler radar typically only works for storms at higher than 4,000-feet elevation, making the dust storm difficult to detect. Ground spotters in Eloy then began calling to say something major was about to happen.

Weather service officials snapped this shot as the dust storm they were tracking approached their outpost.
Weather service officials snapped this shot as the dust storm they were tracking approached their outpost.
Image: National Weather Service

At about 7 p.m., meteorologists pin-pointed what appeared to be the storm moving on their radar screens, and examined it with a new "dual-polarization" radar that gathers extra detail.

NWS workers stepped outside to take the picture and video published on the Web page. Visibility dropped to zero in some places, officials note, and the cost due to damages on the ground is likely to be "substantial."

Then came the storm of media calls: NWS officials conducted 40 interviews in the next 24 hours, and at least 1,000 news articles were published about the event.

More than 100 dust storms have been logged by the weather service in the last 10 years, but the reports states that "while records of most widespread, most intense, largest, etc., dust storms are not kept, NWS meteorologists that have worked in Phoenix for almost 30 years have said this was one of the most significant dust storms they have experienced."

Judging by the number of drain cleaning service and pool-maintenance vans we've seen out and about in the last couple of days, many Valley residents are still dealing with the aftermath.

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