By Ray Greely / ADOT Meteorology Intern

Monsoon rains are forecast to return to Arizona on Tuesday. Strong winds, blowing dust, heavy rain and lightning often accompany these storms from June through September.

Have you ever wondered what climatological features are responsible for these seasonal thunderstorms or why these storms often move from the east to west? We'll explain that and look at the reason why Tropical Storm Javier may bring heavy rain to the state this week.

The monsoon high pressure system

One critical ingredient to the Arizona monsoon is the sub-tropical or monsoon high that's part of a high-pressure belt forming along the northern flank of the tropics. During the winter and spring, this belt moves well south of Arizona, allowing for a westerly steering current to control Arizona’s weather. In the summer, it shifts north. This weakens and can even reverse the westerly flow depending on where it positions itself in relation to the state.

Winds flow out of any high pressure system in a clockwise direction. It is common for the monsoon high to become centered just east of Arizona and then drift north and south throughout the summer. If it moves south of the state, the flow around it will bring dry midlevel winds from the west and, usually, hot and dry weather. When it moves north of the state, a more tropical flow allows tropical moisture and disturbances to enter the state from the east.

System movement

Moisture sources

Thee significant moisture sources influence the Arizona monsoon.

The first is the Gulf of Mexico, where a high pressure system known as the Bermuda High becomes centered over the western Atlantic Ocean east of the southeast U.S. coast, bringing midlevel winds and moisture into central Mexico. While a significant amount of low-level moisture is blocked by mountain ranges, mid- and upper-level moisture can eventually settle in the Mexican states of Chihuahua and Sonora and then get funneled into Arizona.

Moisture from the Gulf of California is distributed into Arizona via a process known as the gulf surge. This begins when tropical disturbances bring unsettled and relatively cooler weather to areas adjacent to the southern Gulf of California while hot dry conditions persist in the areas to the north. A pressure gradient between the two regions forms, and air begins flowing toward the low pressure area in the hot north. This breeze transports low-level moisture through the northern gulf region into Arizona.

The third source is tropical cyclones that form in the eastern Pacific and wander close to the west coast of Mexico. Occasionally they get caught in the flow and can reach Arizona in the form of remnant tropical moisture. This is the weather pattern expected to occur this week as Tropical Storm Javier sends moisture into Arizona.

Thunderstorm Development

Intense heat and rugged terrain

Arizona’s rugged terrain and summer heat provide another important ingredient for thunderstorm development: rising air and instability. Since air cools and expands as it rises and cool air is unable to hold as much moisture as warm air, rising air can become saturated and begin to condense water in the form of clouds. Wind patterns that force air up into mountainous regions and Arizona's relentless summer sunshine that rapidly heats the ground both encourage air to rise. If the atmosphere has a sufficient amount of water vapor, thunderstorms may form.

Cloud stages

Outflow Boundaries

Rising air that fuels thunderstorms will come back down eventually. When thunderstorms reach maturity, this displaced air becomes colder than its environment, creating a downdraft that falls rapidly. When the downdraft reaches the ground, it spreads out in all directions, much like water pouring out of a glass onto the floor. These sometimes-violent winds, known as thunderstorm outflow boundaries, can cause blowing dust and, if strong enough, can force air upward to form new storms. These boundaries occasionally collide with one another and displace even more air upward, aiding in the development of strong or severe thunderstorms.

Editor's Note: ASU’s School of Geographical Sciences & Urban Planning has partnered with ADOT to place graduate-level meteorology students in the ADOT Traffic Operations Center. This allows ADOT to have better information about weather conditions and more quickly determine how to deploy crews and communicate with the public.

By Kira Frost / ADOT Meteorology Intern

If you've lived in Arizona very long, you've probably heard the terms dust storm and haboob a few times. You may not have known there are three different types of dust storms with unique characteristics.

Below are the three types of dust storms and their causes.

Winter storms: These storms are caused by strong winds over a large desert areas gusting dust up into the air, creating hazy conditions. These storms, which usually occur from winter to early spring, can reduce visibility and air quality.

Monsoonal storms: Haboobs originate from monsoonal storm activity and the severe atmosphere that also creates thunderstorms. This atmosphere causes a down draft or microburst of air that blasts downward, kicking dust into the air and creating a wall of thick dust. Haboobs can travel quickly and be as wide as 100 miles. Avoid travel when these strong monsoon storms hit.

Channelized Dust: This phenomenon is different that the two above, which can be predicted, seen and thus avoided. Channelized dust has proven more fatal and hazardous for Arizona highways because it can occur during any season and pop out of nowhere. When the right amount of forceful wind travels over dry deserts, a channel of dust can kick up and spiral across a highway, reducing visibility to nothing in mere seconds.

Since you may encounter these storms unexpectedly, you need to be prepared. ADOT's Pull Aside Stay Alive safety campaign aims to keep drivers safe when the dust blows.

Tips for drivers caught in a dust storm:

• Avoid driving into or through a dust storm.
• If you encounter a dust storm, check traffic immediately around your vehicle (front, back and to the side) and begin slowing down.
• Do not wait until poor visibility makes it difficult to safely pull off the roadway – do it as soon as possible. Completely exit the highway if you can.
• Do not stop in a travel lane or in the emergency lane; look for a safe place to pull completely off the paved portion of the roadway.
• Stop your vehicle in a position ensuring it is a safe distance from the main roadway and away from where other vehicles may travel.
• Turn off all vehicle lights, including your emergency flashers.
• Set your emergency brake and take your foot off the brake.
• Stay in the vehicle with your seat belts buckled and wait for the storm to pass.
• Drivers of high-profile vehicles should be especially aware of changing weather conditions and travel at reduced speeds in high wind.
• A driver’s alertness and driving ability are always the top factors in preventing crashes. It is your responsibility to avoid distracted or impaired driving.

Editor's Note: ASU’s School of Geographical Sciences & Urban Planning has partnered with ADOT to place graduate-level meteorology students in the ADOT Traffic Operations Center. This allows ADOT to have better information about weather conditions and more quickly determine how to deploy crews and communicate with the public.

By John Halikowski / ADOT Director

For those of us in Arizona, summertime means much higher temperatures during the day, not-so-cool nights in the desert, and the monsoon that brings memorable lightning shows and dust storms. The weather officials designate monsoon season from mid-June to mid-September. At ADOT, our crews remind everyone of the do’s and don’ts of driving through a dust storm with our "Pull Aside, Stay Alive" education campaign. Your safety is important to us at ADOT, so I encourage you to follow our messages and avoid driving into or through a dust storm.

ADOT is doing more than an education campaign. We are partnering with Arizona State University in having a meteorology graduate student work with our Traffic Operations Center in Phoenix, monitoring weather and providing real-time insight into changing conditions. We can deploy our crews and communicate to the public on pending weather conditions, like dust storms, to make our roads safer for travel, especially during the monsoon. It is a unique partnership I’m proud exists at the agency.

This past month, we witnessed the need to close I-10 in both directions several times near San Simon due to blowing dust from a neighboring farm. Through that effort, we are witnessing enhanced coordination with multiple state agencies. Besides the law enforcement activity associated with closing a major highway during a dust storm, it sometimes requires us to work with other agencies like the Arizona departments of Agriculture or Environmental Quality to assist with dust mitigation efforts. As always, the Arizona Department of Public Safety is a key partner.

For the future, ADOT will work closely with the Arizona Department of Public Safety on implementing variable speed limits when weather conditions like dust storms warrant a reduction in the speed limit for safety.

Drive safely this summer. And wait on washing your vehicle until the monsoon ends!

This post originally appeared on ADOT Director John Halikowski's 
   LinkedIn page. He has led the agency since 2009.

By Doug Pacey / ADOT Communications

With Monsoon Awareness Week underway, we're highlighting the Arizona Department of Transportation's Pull Aside, Stay Alive campaign emphasizing dust storm safety.

The campaign, which began in 2012, urges motorists to avoid driving into dust storms. If you are caught in low-visibility blowing dust, do the following: pull off the roadway as far as possible, turn off all vehicle lights, set the emergency brake and wait out the storm.

Wait. Turn off all vehicle lights?

Yes, and here’s why: If your car’s lights remain on, any vehicles coming up from behind could use the lights as a beacon, crashing into your car. Remember, you’ve pulled off the roadway to avoid other vehicles. Don’t leave on the lights and increase the possibility of attracting one.

Here’s the full list of “Pull Aside, Stay Alive” dust storm safety tips:

• Avoid driving into or through a dust storm.
• If you encounter a dust storm, immediately check traffic around your vehicle (front, back and to the side) and begin slowing down.
• Do not wait until poor visibility makes it difficult to safely pull off the roadway – do it as soon as possible. Completely exit the highway if you can.
• Do not stop in a travel lane or in the emergency lane. Look for a safe place to pull completely off the paved portion of the roadway.
• Turn off all vehicle lights, including your emergency flashers. You do not want other vehicles approaching from behind to use your lights as a guide, possibly crashing into your parked vehicle.
• Set your emergency brake and take your foot off the brake.
• Stay in the vehicle with your seat belts buckled and wait for the storm to pass.
• Drivers of high-profile vehicles should be especially aware of changing weather conditions and travel at reduced speeds.

By Caroline Carpenter / ADOT Communications

Anyone who has spent a summer in Arizona knows that in addition to very hot temperatures, blowing dust can be an issue. As an intern, ASU meteorology student Paul Panhans has been working with ADOT to better prepare the agency for weather events. He recently shared what forecasters look for when predicting blowing dust and where some of the trouble spots are located.

Southern Arizona

In the southern Arizona, especially Pima and Cochise counties, the one thing meteorologists look for when forecasting dust is sustained winds of 20 knots (23 mph) with gusts to 30 knots (34 mph) or more. April and May are the months with the greatest chances of blowing dust. Forecasters must consider the length of time since the last rain event when predicting blowing dust. In desert areas, it doesn't take long for the soil to dry out after it rains.  Also, dry areas in front of a storm can kick up blowing dust.

Other hotspots for blowing dust include the area east of Tucson known as the Willcox Playa to the New Mexico line. Blowing dust is typically an issue here when wind is from the south/southwest.

Another place meteorologists regularly see blowing dust is along Interstate 10 from Marana to Phoenix. The area around Picacho Peak (mileposts 208-214) can be especially busy. Winds are usually out of the southeast when blowing dust kicks up. This area is also prone to haboobs, especially in the early part of the monsoon.

Northern Arizona, including Flagstaff

While north-central and northeastern Arizona is usually not affected by large haboobs, these areas sometimes see blowing dust ahead of cold fronts. When this happens, there will be 30 mph sustained winds with gusts up to 55 mph. If it’s a dry spring, early summer monsoon outflows can produce blowing dust.

Hotspots for blowing dust in this forecast area include:

I-40 West of Winslow: “Tucker Flat” 

Chinle Valley

Northwest Arizona

Blowing dust is more likely in northwest Arizona when there hasn't been rain. Gusty winds up to 30 mph are another sign meteorologists look for. The first few storms at the beginning of the monsoon are the most likely to cause trouble. The main hotspot for blowing dust is Red Lake, north of Kingman, as seen in the map below. Thunderstorm outflows that come in from the north/northeast can hit Red Lake and quickly drop visibility. State highways like State Route 66 and US 93 are affected by these thunderstorm outflows.

East of Kingman, the risk of blowing dust decreases as the elevation starts to increase and the amount of vegetation increases. Areas along Highway 95 near Lake Havasu rarely have issues with blowing dust.

Kingman and surrounding area

Fort Mohave and surrounding area

Agricultural development near Fort Mohave can cause occasional blowing dust.

Central Arizona and Phoenix

The biggest problem in central Arizona and Phoenix is usually not large haboobs but small-scale blowing dust. This is tough to diagnose and to forecast. The greatest chance of these smaller dust storms is during a drought and when a field that used to be vegetated has been plowed.

Problem-prone areas include:

• I-10 near Picacho Peak
• Mormon Trail
• Casa Grande
• Maricopa to Sun Lakes along State Route 347

On Monday, we kicked off Arizona Monsoon Awareness Week with a brand new video, an invitation to #HaboobHaiku and a list of tips for drivers who encounter a dust storm…

You know that list, right? You can find it easily at PullAsideStayAlive.org, and it offers some really crucial advice.

We share it every year around this time to make sure motorists are ready for the dust storm season ahead. However, one of the tips seems to always get a lot of questions, so we thought we’d tackle it here today.

We’re talking about the guideline that suggests drivers turn off all vehicle lights, including emergency flashers, once they have pulled safely off the road.

So, why should you turn off your vehicle lights, once you’ve pulled aside?

Arizona Department of Public Safety spokesman Bart Graves explains that when a dust storm hits, visibility can be reduced to zero very quickly.

“In a dust storm situation, the sunlight is completely blocked,” he said. “It’s like nightfall, without the visibility of nightfall.”

Graves says that when a vehicle is pulled off the highway and its lights are on, other motorists will likely think the car is traveling on the road and will try to “follow” the lights. Because of the reduced visibility and confusion that a dust storm creates, those other motorists won’t necessarily realize that the vehicle is stopped off the roadway and may wind up crashing into the parked car.

“If you keep your lights on, even if you’re off the highway … you may be struck at a high rate of speed, because they think your car is moving,” Graves said.

Graves advises drivers to turn off all vehicle lights, once they’ve safely pulled off the road. Drivers should then set their emergency brake and take their foot off the brake. After that, motorists need to stay in the vehicle with their seat belts buckled until the storm has passed.

When pulling off the highway, Graves said that drivers should pull over to the right (not to the left, “that’s an extremely dangerous spot,” Graves said) as far off the road as possible.

One of the biggest mistakes people make is thinking they can easily just power through a dust storm, Graves said.

“We’ve seen these situations where the visibility decreases rapidly,” Graves said. “That’s a very dangerous situation to be in.”

For a complete list of safe driving tips, visit PullAsideStayAlive.org, and please share with friends and family.

It’s that time of year again when we remind you to “Pull Aside, Stay Alive” if you ever encounter a dust storm...

Even if you’ve heard the message before, we hope you’ll keep listening and help us spread the word because there are plenty of young drivers and new Arizona residents who might not yet understand the real dangers of driving into a dust storm.

Know anyone who fits that description? We encourage you to educate them about dust storm safety. Of course, you can point them in our direction!

From websites and blog posts to Tweets and haikus, we have a lot to share, including today’s video, a brand new public service announcement that was created by ADOT and its partners at the Governor’s Office of Highway Safety, the Arizona Department of Public Safety and the National Weather Service.

Haboob Haiku

In addition to the video and a new radio public-education announcement, ADOT will be using social media all this week to engage Arizonans in spreading the word to “Pull Aside, Stay Alive.”

You know what that means: the “Haboob Haiku Challenge” is back for a fourth year!

You can read in detail why we #HaboobHaiku in this blog post, and you’ll see that our main focus each year is to get people talking about the dangers of driving in dust storms. By building awareness about dust storm safety, we hope more drivers will know what to do when that next dust storm hits.

But this year we’re putting a slight twist on the tradition…

Instead of asking you to focus your poems on the “Pull Aside, Stay Alive” message as we have in the past, this monsoon season we’d like for you to show off your creativity by telling us where you'll be when the dust settles with haikus about how to drive safely during dust storm events. Here’s an example:

When the dust settles

I will be safe off the road

With my seatbelt on

Don’t forget to use the #HaboobHaiku hashtag. You can Tweet your poems to us @ArizonaDOT or post them to our Facebook page. You’ll also want to remember that haiku is a type of poetry that conforms to a certain syllable structure. These poems are traditionally written in three lines – the first line consists of five syllables, the second line has seven and the third ends the poem with five.

Finally, we want to make sure you see (and share) these driving tips. They’re not just inspiration for your haikus, but important reminders for drivers who encounter a dust storm.

• Avoid driving into or through a dust storm.
• If you encounter a dust storm, check traffic immediately around your vehicle (front, back and to the side) and begin slowing down.
• Do not wait until poor visibility makes it difficult to safely pull off the roadway – do it as soon as possible. Completely exit the highway if you can.
• Do not stop in a travel lane or in the emergency lane; look for a safe place to pull completely off the paved portion of the roadway.
• Stop your vehicle in a position ensuring it is a safe distance from the main roadway and away from where other vehicles may travel.
• Turn off all vehicle lights, including your emergency flashers.
• Set your emergency brake and take your foot off the brake.
• Stay in the vehicle with your seatbelts buckled and wait for the storm to pass.
• Drivers of high-profile vehicles should be especially aware of changing weather conditions and travel at reduced speeds in high wind.
• A driver’s alertness and safe driving ability are always the top factors in preventing crashes. It is your responsibility to avoid distracted or impaired driving.

For more information, please visit PullAsideStayAlive.org.

By Doug Pacey
ADOT Office of Public Information

Monsoon season is upon Arizona. The powerful, ear-splitting thunderstorms don’t always arrive alone, though. Sometimes, they’re preceded by towering, blackout-inducing dust storms, also known as “haboobs.”

Dust storms can be extremely dangerous for motorists and the Arizona Department of Transportation is serious about dust storm safety.

ADOT’s “Pull Aside, Stay Alive” dust storm awareness campaign urges motorists to avoid driving into a dust storm. If a dust storm is in the far-off distance, do not drive toward it. If it is immediately ahead, slow down, pull off the highway as far as possible, turn off all vehicle lights (including emergency flashers and brake lights so other vehicles do not follow) and wait until the storm passes.

We want this information to stay with you, especially when you’re in your vehicle. So, we created a dust storm playlist. Load it onto your smartphone, stream it on Spotify, upload it to the cloud or burn a CD – people still do that, right? – then crank up your car stereo and rock out to the not-so-underlying musical messages of dust storm safety.

ADOT’s Dust Storm Playlist

1. “Should I Stay or Should I Go?” – The Clash
When it comes to dust storms, always stay and never go.

2. “I Will Wait” – Mumford & Sons
Actual lyrics:
These days of dust
Which we’ve known
Will blow away with this new sun
So, be like Mumford and wait.

3. “Stayin’ Alive” – Bee Gees
In our hearts, we believe Barry, Robin and Maurice Gibb pulled aside to write “Stayin’ Alive.”

4. “Livin’ on a Prayer” – Bon Jovi
So what if you’re “halfway there?” Drive into a haboob and you will be livin’ on a prayer.

5. “Danger Zone” – Kenny Loggins
You want to take the highway to the danger zone? That’s a negative, Ghost Rider.

6. “All You had to do was Stay” – Taylor Swift
Stay put. Seriously, that’s all you have to do.

7. “Dust in the Wind” – Kansas
It’s mandatory for a song about dust to be included in a dust storm playlist, right?

8. “Ready, Set, Don’t Go” – Billy Ray Cyrus
Our achy, breaky heart will shatter if you don’t heed our “Pull Aside, Stay Alive” advice.

9. “Sandstorm” – Darude
Resist the urge to crack open the glow sticks from your vehicle’s emergency kit – remember, no lights! – when listening to this awesomely titled Finnish trance music.

Bonus Track
10. “Sasquatch” – The Winebottles
You never know where Bigfoot might pop up.

The official National Weather Service Arizona monsoon period, which runs June 15 to September 30, brings a variety of travel concerns in addition to dust storms, including flash flooding, rain-slicked roads and high winds. When adverse weather conditions are present, ADOT urges motorists to drive with caution or delay travel. For more information, please visit ADOT’s Transportation Safety page.