What it means
A dust storm is what happens when the wind picks up the desert and puts it in front of your windshield. Locals use the phrase loosely and correctly: the mile-high wall rolling in from the south on a July evening is a dust storm, and so is the gritty, gray afternoon when a dry spring front scours the fields around Casa Grande. The first kind has its own name, the haboob, and its own argument about that name. The second kind just has wind.
You will hear the term most often from the highway signs and the Arizona Department of Transportation, which long ago decided that the useful thing to say about dust is not what it is but what to do in it. The answer is a rhyme every Arizona driver can recite: Pull Aside, Stay Alive. The unlucky learn it on I-10.
The full monsoon driving playbook, including the flood rules, lives in the monsoon field manual. This page is about the word and the warning.
Where you’ll meet it
Phone alerts from the National Weather Service, overhead message boards on the 10 and the 8, ADOT’s summer campaign, and any drive to Tucson between June and September. Dust storms can happen in any month, but the monsoon produces most of them.
Where the word came from
Nobody coined “dust storm”; it is plain English, used across the American West since long before Arizona had freeways. What changed is the official vocabulary around it. The National Weather Service issues a Dust Storm Warning when blowing dust is expected to cut visibility to a quarter mile or less, generally with winds of 25 mph or more. On November 1, 2018, the Service redrew those warnings as storm-based polygons, the format it uses for tornadoes and severe thunderstorms, and added a lesser Blowing Dust Advisory for events that make driving hazardous without meeting the warning bar. A warning now covers the strip of desert the storm is crossing rather than a whole county.
The driving slogan came from ADOT. Its Pull Aside, Stay Alive campaign has produced public service announcements since at least 2013, with new rounds in 2014 and 2018, and the steps have not changed: check traffic and slow down, exit the highway if you can, never stop in a travel lane, turn off every light including your flashers, set the emergency brake, take your foot off the brake pedal, stay buckled and wait. The counterintuitive part is the lights. A driver blinded by dust steers toward the only thing visible, which is your tail lights, and assumes you are still moving.
In 2020 ADOT added hardware to the slogan. A dust detection and warning system, which the agency described as the first of its kind, went live on ten miles of I-10 between Eloy and Picacho Peak, mileposts 209 to 219: 13 visibility sensors, a weather radar on a tower at the State Route 87 junction, cameras, message boards and variable speed limit signs that can step down from 75 mph to 35 mph as the dust thickens.
What it is not
A dust storm is not automatically a haboob. The haboob is the thunderstorm outflow kind, a monsoon event with a visible wall. A gray, all-day blow behind a winter cold front is a dust storm with no wall and no storm cloud behind it, and it can be just as blinding on the interstate.
The fine print
The numbers explain why ADOT talks about dust the way other states talk about ice. A study by National Weather Service meteorologists and a University of Arizona researcher, reported in 2016, counted 157 deaths and 1,324 injuries in 1,521 dust incidents on Arizona highways from 1955 to 2011. That makes dust the third-deadliest weather hazard in the state, behind extreme temperatures and flash floods, and the leading weather cause of injury. Nearly half of the incidents were on interstates through the southern desert, with a notorious spot on I-10 near San Simon, close to the New Mexico line.
The I-10 corridor between Phoenix and Tucson is the stretch locals worry about, because the freeway crosses open farmland and dry ground at full speed and carries the heaviest traffic in the state’s desert. ADOT chose the Eloy to Picacho Peak segment for its detection pilot because it is prone to sudden blowing dust, and paid for the roughly $6.5 million system partly from a federal FASTLANE grant tied to widening the freeway.
Scottsdale itself rarely sees the worst of it. The city sits on the north side of the metro, and many storms thin out before they arrive. The danger is the drive out: the airport run on the 101, the trip to Tucson, the late-summer return from a weekend on the day trip circuit. ADOT’s best advice is the dullest one. If a severe storm is on the move, delay the trip. The desert will still be there in an hour, and so will you.