How Weather Changes Spread ‘Fungal Storms’

You may not have heard of Valley Fever unless you are from the Desert Southwest, but this soil-borne disease is quietly spreading into new parts of America — and changing weather patterns are predicted to help it travel farther than ever before.

What's being described as "fungal storms" isn't a new kind of weather phenomenon; rather, it's a combination of conditions where microscopic spores ride on dust storms, hurricane winds and floodwaters.

As climate change creates hotter, drier conditions punctuated by extreme rain events, these nearly invisible threats are expanding their potentially deadly reach.

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From Desert Southwest To Canadian Border

Valley Fever infections have been historically concentrated in Arizona, California, New Mexico and parts of Texas — regions where the coccidioides fungus naturally thrives in arid soil.

“When it rains, we see a bloom of this fungus in the dirt or in rodent burrows. And then when things dry out, those spores become airborne. So the change in weather patterns with where the rain falls or doesn't fall and where there's heat and dryness changes the impact. We've seen that from year to year, but there may be longer term cycles in terms of decades or even centuries,” explained Dr. John Galgiani, the director of the Valley Fever Center for Excellence at the University of Arizona College Of Medicine, Tucson.

California has already seen at least 2,197 cases of Valley Fever for 2026, which is very close to the 2,996 cases reported for all of 2025, according to state health statistics.

Cases are also increasingly being identified in Oregon and Washington state, with experts predicting continued expansion into the Midwest and potentially reaching Canada within decades.

A Disease That Devastates

Valley Fever isn't your typical respiratory infection. While the symptoms can mimic the common cold or flu, this fungal assault can linger and without the specific blood test, an accurate diagnosis can be easily missed.

"One of the things that distinguishes Valley Fever is it's often weeks to months in illness. It's not just days. So it's really often a lot more like a pneumonia,” says Dr. Galgiani.

“For a small percentage of people, it goes out of the chest through the bloodstream to other parts of the body and can cause meningitis, which is lethal if it's not treated,” he warns.

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A National Disease In Disguise

Dr. Galgiani believes Valley Fever should be considered a national problem because of tourism: "It's a national disease because people visit the Grand Canyon State all the time."

Visitors can inhale spores during their trips and develop symptoms weeks later, back in their home states, where local doctors may not recognize the disease.

That’s why Dr. Gagliani hopes it becomes as familiar to us as Lyme disease, which is also a largely regional problem but is much more well-known.

"I think awareness is the protection. Knowing about it and getting the diagnosis very early is the best way to really improve your health."