A menacing dust storm is set to barrel through Arizona within hours, causing alarm as it may carry dangerous fungal spores capable of inducing a life-threatening illness.
Central and southern Arizona are bracing for the so-called ‘fungal storm,’ impacting hundreds of thousands of residents. This has prompted the National Weather Service to issue a blowing dust advisory for the affected regions on Wednesday.
The forecast predicts wind gusts reaching up to 55 mph, set to hurl dense dust, debris, and soil across cities including Phoenix and Tucson between 6 pm and 1 am ET (3 pm to 10 pm local time).
Primarily impacting parts of Maricopa, Pinal, Pima, and Santa Cruz counties, the storm threatens areas like the suburbs of Phoenix—Buckeye, Avondale, Ahwatukee, and Queen Creek. An estimated 1.5 million people fall within the advisory’s path.
With the National Weather Service predicting that visibility will drop to a mere quarter of a mile on Wednesday, travelers are cautioned to expect perilous driving conditions throughout the night.
Another concern during an Arizona dust storm is the microscopic fungus called Coccidioides, which is blown into the air from local soil and can trigger the potentially fatal lung infection Valley fever when inhaled.
NWS warned in a statement: ‘Persons with respiratory problems should make preparations to stay indoors until the storm passes. Be ready for a sudden drop in visibility to near zero.’
Arizona officials have not confirmed that the dust storm will contain the fungus, but the CDC has warned that Coccidioides is found throughout all of Arizona and its neighboring states in the Southwest.
A massive dust storm seen passing over Arizona. These storms can carry fungal spores which cause Valley fever (Stock Image)
A major blowing dust advisory has been issued across central and southern Arizona on August 19, 2026
NWS added that conditions throughout Arizona on Wednesday, including the chance for severe thunderstorms and high winds, will make it possible for a phenomenon known as haboobs to form.
These are huge walls of dust kicked up from the dry ground right when the soil is at its driest. The combination of extreme heat and drought plus monsoon winds create more frequent and intense dust storms carrying Coccidioides.
For people caught outside during a fungal storm, the spores turn into growing fungal cells that the immune system typically fights off, causing mild flu-like symptoms such as fever, cough and headaches in most patients.
However, severe infections can spread to the organs and bones and become fatal. The CDC has warned that between 15 and 30 percent of all cases of pneumonia in the Phoenix and Tucson areas are caused by breathing in Coccidioides.
NWS warned that individuals suffering from heart disease and chronic respiratory conditions such as asthma will be among those at the greatest risk for complications.
‘Those most at risk may feel better if they avoid outside exercise today, keeping windows and doors closed to help reduce exposure,’ the weather agency added.
Those driving through Arizona have also been warned to be ready for potentially fatal road conditions, as blowing dust can make it impossible to see anything within seconds.
‘If you encounter blowing dust or blowing sand on the roadway or see it approaching, pull off the road as far as possible and put your vehicle in park. Turn the lights all the way off and keep [your] foot off the brake pedal. Remember, “Pull Aside, Stay Alive,”‘ NWS advised in their alert.
Pictured: A dust storm was captured blowing overhead in Phoenix, Arizona on August 4, 2026
Pictured: A 3D illustration showing Coccidioides immitis, the pathogenic fungi that resides in soil and can cause Valley fever in the US Southwest
At the same time as the dust and thunderstorms, an Extreme Heat Warning has been issued throughout the same parts of central and southern Arizona through Friday.
Temperatures are expected to compound breathing issues outside, with the heat index approaching 110°F.
The heat index is the ‘feels like’ temperature, which is hotter when the air is more humid. On a 90-degree day, high humidity can make the ‘feels like’ temperature reach 105°F.
‘Overexposure can cause heat cramps and heat exhaustion to develop and, without intervention, can lead to heat stroke,’ NWS said.
The extreme forecast is being fueled by a massive heat dome, a system of high pressure, blanketing the western half of the US. The pressure traps heat and humidity close to ground like a lid on a boiling pot.
This is a breaking story. More details to follow.
Strong thunderstorms have also been forecast for southern Arizona, potentially causing a dust storm phenomenon called a haboob to form
The CDC notes at least 11 states carry a risk for Coccidioides fungal spores that can be blown into the air by dust storms, including Arizona