In the hills near Los Angeles, the Blue Cut Fire just ripped through 36,000 acres, taking dozens of homes along with it, spurring a major evacuation, and even requiring temporary highway closures. But the merciless flames of the Blue Cut Fire almost pale in comparison with the flood of wildfires across the Golden State, and the West at large, in an era when the wildfire season is growing longer and more aggressive every year.
Climate change is the reason why, and researchers are discovering that the cost of wildfires may be bigger than we imagined: They’re tracking deadly “smoke waves” that sweep the landscape, causing serious respiratory health problems.
If you’ve ever been near an active wildfire, you’ve probably noticed the haze caused by particulate matter as hot winds carry it across the landscape. Ash and debris can land far from an original fire, while the atmospheric disturbance can generate disturbingly stellar sunsets. In heavy fires, the murk of pollution can be so thick that day practically turns into night, and depositions of ash can pile up on distant windshields and drift through the air like an advance guard.
Researchers at Harvard and Yale got curious about wildfire haze and they studied conditions across the West to learn more about how far it spreads, what it does to the environment, and who is affected by it. What they found was deeply troubling: An increase in what they call “smoke waves,” in which pollution remains sustained and high for at least two days.
When you’re camping and the smoke of the fire makes you cough, driving you to the other side, you have an inkling of what it’s like to be in a smoke wave. But instead of lasting for a few hours while you make s’mores, it lasts for days, and it’s impossible to escape.
Inhaling particulate pollution is incredibly hard on your lungs, especially if you have an existing respiratory condition like asthma or chronic pulmonary obstructive disease. And it’s not localized to the area right around the fire. In 2016, when the Fort McMurray Fire ravaged Alberta, people in Michigan were going to the doctor’s office complaining of respiratory discomfort.
The researchers estimate that starting in the 2040s, 82 million people across the West will be in the direct path of smoke waves, nearly doubling the number of people currently at risk. Highly populated regions are of particular concern, like the San Francisco Bay Area, which was name checked because of its proximity to the kind of dry, fuel-laden conditions that allow wildfires to thrive.