Image of a thunderstorm in a field
By Gary Fitzgerald

On Nov. 21, 2016, a fierce thunderstorm occurred over the city of Melbourne, Australia. It caused what was called a “mass asthma event”: Eight people died due to sudden onset of asthma symptoms and 8,500 more went to emergency departments.

The severity of these asthma cases brought to the forefront the phenomenon known as “thunderstorm asthma.”

What exactly is thunderstorm asthma?

When heavy thunderstorm winds occur, they lift grass, tree and weed pollen and mold spores into the air. Hard-driving rain saturates the allergens and separates them into even tinier particles. The heavy thunderstorm winds spread those tiny particles into the air we breathe.

When inhaled by someone with allergic asthma, pollen and mold spores can inflame airways and cause a flare. Even someone with mild allergy symptoms may have breathing problems during thunderstorms.

Why is thunderstorm asthma life-threatening?

It may be some people with allergic asthma are simply unprepared for the sudden onset and severity of symptoms following thunderstorms.

In rainstorms, there is often a burst of pollen into the air when wind picks up, but the pollen is so saturated and heavy that it returns to the ground and lies still. In thunderstorms, winds are much stronger and pollen stays in the air longer.

Does thunderstorm asthma happen in the United States?

Thunderstorm asthma is uncommon. Severe cases have been reported in Australia, England and Italy through the years – and there likely have been cases in the United States, just not on a wide-ranging level like what occurred in Melbourne.

A 2008 study published in the medical journal Thorax revealed that 24,350 asthma-related emergency department visits in Atlanta from 1993-2004 occurred on days following thunderstorms.

Thunderstorm asthma could become more common due to climate change. Climate scientists say pollen allergy seasons could become longer and thunderstorms more potent, with heavier rains and stronger winds.

How can people with asthma prevent symptoms during and after thunderstorms?

First things first, talk to your healthcare provider and find out if you’re allergic to pollen or mold spores. You may need to undergo a simple skin or blood test to find out for sure. If it’s determined you have a pollen or mold allergy, then appropriate measures can be taken to manage the condition – either with avoidance or medication.

Staying inside during a thunderstorm is obviously an important way to prevent asthma symptoms. Be sure to keep windows closed. If you were outside during heavy winds, taking a shower and washing your clothes will help remove pollen.


icon-angle icon-bars icon-times