Low Desert Almanac

Dust-Storm Decision Flow

A short decision path for driving, for being at home and for being outdoors when a dust storm arrives, following Arizona Department of Transportation guidance.

Monsoon

A wall of dust is coming. What do I do?

Where are you when it arrives?

A dust storm does not build the way a rain storm does. It crosses the last mile in seconds, and the decision is made before you can see anything at all.

ADOT: Pull Aside, Stay Alive

The state transport department’s dust-storm campaign, for a driver caught on the road, in the order the campaign gives it. The driving path on this page follows the same five steps.

  1. See it, slow down, and start looking for a way off the road

    The campaign’s instruction is not to drive into the wall at all, and its first practical step is to read the traffic around you (behind and to the sides) before you begin slowing. A dust storm is not a thing to drive through carefully; it is a thing to be out of the way of.

  2. Pull entirely off the paved surface of the road

    Off the roadway rather than onto the shoulder. The campaign is explicit that the travel lane and the shoulder are the wrong places to stop, which is why the step is to leave the pavement altogether and go as far from the traffic as the ground allows.

  3. Turn off every light, including the emergency flashers

    Headlights, tail lights and the hazards. ADOT gives the same reason the county and the forecast office do: in near-zero visibility a driver coming up behind you steers toward the only thing they can see, and your lights are it.

  4. Set the parking brake and take your foot off the brake pedal

    Brake lights are lights. With the emergency brake set, the pedal can come up and the tail lights go dark, which is the point of the step rather than an oversight in it.

  5. Stay in the vehicle, belted, until it passes

    Do not get out to look, film or move anything. The dust is abrasive and the wind behind it carries debris, and the inside of a stopped vehicle is the safest place available once you are off the road.

ADOT Pull Aside, Stay Alive, Arizona Department of Transportation. The campaign’s own handout is quoted further down.

What “half a mile or less” means

1/2 mile or less

The visibility the Phoenix forecast office names when it talks about blowing dust.

The campaign’s own description of how fast that happens is the reason the first step in every path here is the one that happens before you can see anything: "Dust storms in Arizona can reduce visibility to near ZERO in a matter of seconds!"

NWS Phoenix monsoon safety

In a vehicle

Get off the road before you cannot see, and then make yourself invisible.

This is where dust storms kill people, and almost never by choking them. The deaths are crashes: a driver who kept going at 55 as the wall arrived, or a driver parked on the shoulder with the lights on being steered into by somebody behind. The whole path is about those two mistakes.

The path In a vehicle

  1. The moment you see it

    Do not drive into it

    The campaign instruction is the whole of the first step, and it is in capitals for a reason. A dust wall looks passable for the first few seconds and is not passable at all by the time you are inside it.

    “NEVER DRIVE INTO A DUST STORM!” ADOT Pull Aside, Stay Alive (PDF)

  2. Immediately, not when it gets bad

    Get off the pavement, as far as you can

    Off the roadway rather than onto the shoulder, and as far from the travel lanes as the ground allows. The county’s companion instruction is about the timing: the decision is made when you can still see well enough to make it safely.

    “Do not wait until there is low visibility to take action.” Maricopa County monsoon guidance

  3. Before you stop moving

    Never stop in the travel lane

    Not even for a moment, and not even with the hazards on. Stopping where traffic is still moving converts you from a driver into an obstacle in the one place nobody can see obstacles.

    “Never stop on the traveled portion of the roadway.” NWS Phoenix monsoon safety

  4. Once you are stopped

    Turn off every light you have

    Headlights, tail lights and the emergency flashers. This is the step people argue with, and the county and the forecast office both give the same reason: a driver behind you in zero visibility aims at the only thing they can see, and your lights are it.

    “Turn off all of your lights, including emergency lights” Maricopa County monsoon guidance

  5. Then

    Set the brake, take your foot off the pedal

    Brake lights are lights. Keep your seat belt on, keep your foot on the floor, and stay in the vehicle rather than standing outside it in the dust.

    “Stay in the vehicle with your seat belt buckled and wait for the storm to pass.” Maricopa County monsoon guidance

  6. Until it lifts

    Wait it out, and leave slowly

    The campaign’s own figure for how fast this happens is the reason for the whole sequence: visibility goes to near zero in seconds, and it comes back the same way. Do not rejoin the road until you can see the road.

    “Dust storms in Arizona can reduce visibility to near ZERO in a matter of seconds!” ADOT Pull Aside, Stay Alive (PDF)

Why the lights go off

The rule is an argument about what the next driver can see. With the lights on, their sight-line bends toward the only thing in view. With them off, there is nothing to aim at and the line runs straight past.

Two parked cars, and where the driver behind is looking Top: a car stopped with its lights on. A driver behind in dust sees the tail lights and their path curves toward them, ending at the parked car. Bottom: the same car with every light off. The driver behind sees nothing to aim at and their path continues straight past. Lights on driver behind you, stopped the path curves at the lights Lights off driver behind you, stopped nothing to aim at

A drawing of the reason both the county and the forecast office give for the lights-off rule. Not to scale, and not a measurement: the geometry is the whole of it.

The same two rules in every situation

Act before you can see the problem
Maricopa County states it as an instruction: "Do not wait until there is low visibility to take action." Every option on this page closes as visibility falls, and the margin between acting early and acting late is measured in seconds.
Turning your lights off is the counter-intuitive one
Both the county and the Phoenix forecast office say to kill every light, including the hazards. The reason is that a driver behind you in zero visibility steers toward whatever they can see. The diagram on this page draws it.

What people do, and what the guidance says instead

  • Driving on because it looks thin ahead

    The campaign’s own words are "NEVER DRIVE INTO A DUST STORM!", and the visibility figure explains why the look of it is no help: it falls to near zero in seconds, so the thin part you can see is the last part you will see.

  • Pulling onto the shoulder and leaving the hazards on

    The hazards are what the driver behind you aims at. The Maricopa County instruction names emergency lights explicitly: "Turn off all of your lights, including emergency lights".

  • Stopping in the travel lane with the brake lights on

    The forecast office addresses this one directly ("Never stop on the traveled portion of the roadway") and brake lights are lights, so the same reasoning that applies to hazards applies to them.

  • Getting out to film it or to move something

    The dust is abrasive, the wind is carrying debris, and the air is opaque to drivers as well as to you. The guidance is to stay in the vehicle belted or to be inside a building, and there is no version of it that involves standing outside.

  • Waiting for the forecast to be certain

    A dust storm is forecast as a possibility, not as a time and a place. Treating the issuance of a blowing-dust advisory as the trigger is already late: the county’s instruction is to look at the horizon, not the phone.

The campaign’s own line, and the document it comes from

The one instruction ADOT puts in capitals is this: “NEVER DRIVE INTO A DUST STORM!” It is quoted from the campaign’s 2014 handout, which the weather service hosts and this site could open. The document is dated 2014, and it is labelled here rather than presented as a current page: the four steps above are what the campaign says today.

Arizona Department of Transportation: "Pull Aside, Stay Alive" dust-storm safety campaign (PDF hosted by the National Weather Service)

How this works

Method

Why this is a decision path and not a checklist of numbers

Every other monsoon tool on this site ends in a figure of some sort: an inch of rain, a depth of water, a count of days. This one cannot, because the figure that would settle it (how far away the wall is, how thick, how long it will take to cross the last mile) is not knowable from a webpage and is barely knowable from the driver’s seat. The thing that is knowable is where you are when it arrives, and that single fact sorts the guidance cleanly into three answers that hardly overlap.

Driving is the situation that kills people, and it is the only one with a state campaign built for it. At home it is a wind event with a cleaning job attached. On foot it is the worst of the three, because the good options run out in about the time it takes to read this paragraph. The three paths below are ordered the way each has to happen, and the page asks you one question (where are you?) rather than several, because a person reading a tool while a wall is coming has time for one.

What a dust storm actually is

A haboob is a wall of dust carried on the outflow of a collapsing thunderstorm. The storm drops cold air, the cold air spreads out along the ground, and as the front of that cold air races away from the storm it lifts the loose soil of the desert floor and carries it with it. The result is a moving wall that can be a mile high and tens of miles wide, travelling faster than the traffic it catches.

Two things follow from that and both matter on the road. The first is that a dust storm arrives as the edge of something rather than building like a rain shower, so there is no gentle grey-out to read and no time to change your mind halfway. The second is that the dust and the wind are the same event, which is why the at-home and on-foot advice on this page is mostly high-wind advice: the blowing soil is unpleasant, and the debris the wind carries (branches, sheets of roofing, a sign, a trampoline) is what injures people.

The counter-intuitive rule, and why it is not a mistake

Turning your lights off in near-zero visibility sounds like the wrong instruction, and every agency that publishes it knows it sounds that way. The reason it is right is about the driver behind you rather than about you. In a dust wall a driver can see almost nothing (no lane markings, no road edge, no vehicles) but the one thing that registers is a light. Their instinct, and it is a strong one, is to steer toward the one thing they can see. If that thing is your tail lights, you have rebuilt the most dangerous version of the situation: an invisible stationary object with a beacon on it, in the path of a vehicle at speed.

The published guidance is unusually blunt about the details, which is a sign of how often people get them wrong. Maricopa County names the emergency flashers specifically (“Turn off all of your lights, including emergency lights”) so the hazards that feel like the safe choice are the ones the county is warning about. The brake-light half of the rule is quieter and just as real: brake lights are lights, so the parking brake goes on and the foot comes off the pedal. The whole sequence is drawn above, and it is the reason this page puts the lights-off step in debt to the same logic in all three paths, not just the driving one.

Why the travel lane is the wrong answer and the shoulder is not much better

The instruction not to stop in the travel lane is easy to agree with and easy to break. In a dust storm the instinct is to slow to a crawl and stay pointed forward, which is exactly the behaviour the forecast office addresses with one sentence: “Never stop on the traveled portion of the roadway.” Stopping where traffic is still moving converts a driver into an obstacle, in the one place where nobody can see obstacles.

The shoulder has the same problem in a smaller form, which is why the guidance is to leave the pavement altogether rather than to hug its edge. ADOT’s campaign is the version built for a highway: slow down, read the traffic around you, pull completely off the paved surface, kill every light, set the brake, and stay belted in the vehicle. The steps above are that campaign in the campaign’s order. It is worth noticing that it says “stay in the vehicle” at the end, which is the fourth time the same logic has turned up: the safest thing you can be in a dust storm is something stationary, invisible and off the road.

Why a person on foot is the hardest case

On foot there is one good answer and it closes fast. A building blocks the wind and filters the dust; a vehicle does not, and a shade structure definitely does not. City of Mesa’s severe-weather guidance (written for high wind, and applied here because a dust storm is one) says to lie flat in a ditch or a low-lying area with your hands over your head, which is the only instruction that works when there is nothing solid to get behind. The injuries the guidance is written against are to the head from the debris the wind is carrying, so the hands-over-the-head part is not decoration.

The temptation on foot is to keep walking to wherever you were going, and in near-zero visibility next to a road full of drivers who cannot see either, that is the decision that turns a bad ten minutes into an accident. It is also worth saying plainly what this page does not do: it does not cover the health effects of breathing dust. That belongs to the state health department, whose pages would not open to this site, so the limits list says so rather than sourcing the claim from somewhere second-hand.

What to do with the page

Pick where you are and read the path through once, calmly, some afternoon when there is no wall on the horizon. The value of a decision path is that it is already decided: the guidance exists so that the answer is in your head before the two minutes in which it has to be applied, because those two minutes are not a good time to be reasoning from scratch. There are three paths, one question and nothing to calculate, and every line on them traces back to the agency named beside it.

Sources

Where this came from

Every figure this tool uses was read from the source named above on 11 October 2026. Anything still waiting on a check is listed in the site's data notes rather than shown here as if it were settled.

Limits and assumptions

Read this

Before you act on this

This page is a decision path, not a weather product. It has no forecast, no radar and no clock, and it cannot tell you whether a dust storm is near you. Everything on it describes what the agencies say to do once one is in front of you, so it belongs in your head before the day you need it, not on a screen you are reading while the wall crosses the last mile.

  • This is a decision path, not a forecast and not a warning. It cannot tell you whether a dust storm is coming, how large it is or how long it will last. If the National Weather Service has issued a dust advisory, a blowing-dust warning or a severe-thunderstorm warning for where you are, that warning is current information and this page is not. Act on the warning.
  • It cannot see the road in front of you. There is no measurement on this page and none is possible from a webpage: no visibility reading, no distance to the wall, no speed to slow to. The tool reasons from where you are, because the situation is the one thing a reader can state reliably and a driver cannot judge a dust wall’s depth at all.
  • The health effects of breathing dust are not covered here. That is the state health department’s subject, and its pages would not open to this site, so the page says so rather than sourcing the claim second-hand. A person with asthma or another lung condition should take their guidance from a clinician and from the state, not from this page.
  • Two of the sources are not the authority for every road. The county guidance is written for Maricopa County and the state campaign for Arizona highways; this page collects both because a driver crosses both in one journey. Nothing here covers driving in another state or on tribal or federal land.
  • The driving path is the only one with a published campaign behind it. The at-home and on-foot paths are assembled from the county’s, the city’s and the utilities’ severe-weather guidance, applied to a dust storm because the wind and the dust arrive together. They are this site’s assembly of that guidance, and the page says so rather than implying a single agency publishes a dust-storm page for people on foot.
  • Where a city and the utility that owns the equipment disagree, the page keeps both and says which one it uses. The downed-power-line distance is the case: City of Mesa publishes twenty feet and both utilities publish a hundred. The tool uses a hundred feet and prints the disagreement rather than averaging it.
  • The ADOT handout quoted on this page is dated 2014. The four-step campaign behind it is still the guidance ADOT publishes, but the document itself is not current, and the page labels it so a reader can weigh it. Where this page could not open a live page, it says which document it used instead of implying a fresher one.
  • Nothing here covers what to do after the storm about damage, insurance or a roofline. Those are separate subjects with their own guidance, and the monsoon preparation tool is the page for the work on the building.

Questions

Short answers
Why does every agency tell me to turn my lights off in a dust storm?
Because in near-zero visibility the driver behind you can see almost nothing, and a light is the one thing that shows up. Their instinct is to steer toward it, and they are steering at speed. Maricopa County names the emergency flashers explicitly: "Turn off all of your lights, including emergency lights". The counter-intuitive part is real, and the reason for it is the whole point: being visible is not safety here, it is the thing that gets you hit.
Can I not just pull onto the shoulder and leave the hazards on?
No, and the shoulder is specifically the wrong place. The guidance is to pull entirely off the paved portion of the road (off the roadway, not onto its edge) because the shoulder is still within reach of traffic that cannot see it. The forecast office puts the same instruction the other way round: "Never stop on the traveled portion of the roadway." Stopping where vehicles are still moving turns a driver into an obstacle in the one place nobody can see obstacles.
How long does a dust storm last, and how fast does it arrive?
The speed is the part that matters and it is in the campaign’s own words: dust storms in Arizona "can reduce visibility to near ZERO in a matter of seconds". Visibility of half a mile or less is the figure the Phoenix forecast office names when it talks about blowing dust. Because it arrives in seconds rather than building, every option on this page closes as fast as it appears, which is why the first step in the driving path is the one that happens before you can see anything.
What if I am caught outside on foot when the wall arrives?
Get inside a building: not a vehicle, not a shade structure, a building. If there is no building within reach, the city’s severe-weather guidance is to lie flat in a ditch or a low-lying area with your hands over your head, and the same advice applies to a dust storm because the wind and the debris arrive with the dust. A dust storm is a wind event: the injuries to people caught outdoors are from trees, poles, signs and flying material rather than from the dust itself.
Is the dust itself dangerous to breathe?
This page does not answer that, and it says so rather than guessing. The health effects of airborne dust are the state health department’s subject (airborne soil can carry valley fever fungus among other things) and the department’s pages would not open to this site when the page was written. If you have asthma, another lung condition or a reason to be careful, take that question to a clinician and to the state, not to a dust-storm decision path.