Warming Oceans are Creating More Dust Storms and Increasing Valley Fever in the Southwest, NOAA Study Says

Jonathan Belles
Published: May 12,2017
Windblown dust storms have dramatically increased in frequency in the Southwest and may be linked to a rise in valley fever in recent decades, a new study suggests.
The infection rate of valley fever has mysteriously gone up more than 800 percent from 2000 to 2011, according to the study published in the journal Geophysical Research Letters.
"Dust storms in the region have more than doubled between the 1990s and the 2000s. And we see that valley fever is increasing in the same region," said lead author Daniel Tong.

Dust storms spike with Valley fever cases. The nation’s largest number of dust storms from 1988 to 2011 are concentrated in the Southwest states – the same states reporting the nation's highest numbers of Valley fever cases.
(NOAA)

The authors claim an increase in sea surface temperatures in the North Pacific since the 1990s has led to more dust storms.
In fact, ocean temperatures off the coast of Mexico have gone from just slightly above average to more than a half-degree Celsius above average. This change could be just enough to increase the amount of warm, moist air that reaches western Mexico and portions of the Southwest.
These changes also increase thunderstorm activity throughout the year.
Also, the North Pacific waters off the coast of California remained cooler-than-average during this time period. These cool, drier winds allowed soils to dry more efficiently in periods without thunderstorm activity.
(MORE: Crews Begin to Clear Winter's Massive Snowpack in the Sierra, Cascades and Rockies)

Sea surface temperature anomalies off the coast of Mexico in recent decades. Area of anomalies shown.
(Earth System Research Library/NOAA)

Valley fever – also known as San Joaquin Valley fever or desert rheumatism, according to the Centers for Disease Control and Prevention – is an infection caused by a fungus that grows in the soil in the Southwest, Mexico and parts of Central America.
Valley fever can cause a variety of symptoms, but according to the University of Arizona, 60 percent of those who breathe the fungus that spawns valley fever do not get sick at all. In rare cases, valley fever can cause pneumonia-like symptoms that can spread beyond the lungs, and/or meningitis that can eventually be fatal without treatment.
"Coccidioides [the fungus that causes valley fever] is thought to grow best in the soil after heavy rainfall and then disperse into the air most effectively during hot, dry conditions," said the CDC.
These conditions occur most frequently during the monsoon season when thunderstorms often drop large amounts of rain and produce dust storms in the communities surrounding thunderstorms.

This map shows the approximate areas (called “endemic areas”) where Coccidioides is known to live or is suspected to live in the U.S. and Mexico. This map is based on studies performed in the late 1940s and 1950s and also on locations of more recent outbreaks and cases. Coccidioides might also live in similar areas with hot, dry climates that are not shaded on the map.
(Centers for Disease Control and Prevention)

Storms often produce gust fronts that can pick up sand, dust, bugs and any other light objects and throw them high into the sky. Sometimes, these gust fronts produce dust storms that could disperse valley fever.
"Dust storms not only carry the fungus that can cause valley fever, but also can severely damage aircraft engines, disrupt land transportation and erode and damage farms already hit by drought," according to NOAA.
Research continues to strengthen the relationship between wind-borne illnesses and the weather.
Breathing problems caused by weather are nothing new. Australians reported thunderstorm asthma in 2016 after storms blew high concentrations of pollen into Melbourne, causing problems for thousands.
(MORE: Thunderstorm Australia Death Toll From Rare Thunderstorm Asthma Rises to 6; At Least 8,500 Hospitalized)
Dust storms, sometimes known as haboobs, are the third-largest weather-related killer in Arizona, according to a study released in 2016. The number of deaths related to dust could increase if valley fever is directly attributed to dust storms.

MORE: Dust Storms

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