How raging wildfires create hellish skies across the country

The strange effect is now creeping over to the East Coast.

If you live in the Bay Area and happen to peek outside your window, it probably looks a bit like the apocalypse: one giant orange haze in place of what used to be blue and cloudy skies. Surprisingly, this creepy side effect of the wildfires rampaging across 2.5 million acres of the US’s western coast has a pretty simple scientific explanation.

On a typical day, we can thank gases and particles, including water, in the Earth’s atmosphere for scattering light in all directions. Thanks to its itty bitty wavelengths, blue gets scattered way more than other colors. But when extra smoke particles fill our atmosphere, the sun’s longer visual wavelengths, namely orange and red, have a better chance of making it through the smog to give the sky some color. Once they make their way in, these hues, with their longer wavelengths, overwhelm the sky.

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This isn’t all too different from what happens when we see a sunset, according to NASA. When you spy a warm-toned watercolor sky on a pretty summer night, those colors are taking center stage because when the sun is just peeking over the horizon, rays of light have to travel through more layers of the atmosphere, blocking out the more petite wavelengths.

With enough smoke, giant smoke plumes may form starting “fire thunderstorms” that can block out the sun completely, creating some of the eerie darkness that comes along with the odd color, tweeted UCLA climate scientist Daniel Swain.

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The strange effect is now creeping over to the East Coast, creating rusty-gray colored skies where they should be blue and sunny. The smoke that now hovers over places like Washington, DC, is also lowering overall temperatures in the region.

While the look of the sky is undoubtedly something to gape at, please do so from inside your home, if possible. All across the West Coast, and especially in the San Francisco Bay Area, smoke from the fires is making air quality abysmal. The smoke particles in the air can reach deep into the lungs, causing inflammation and injury to the lining, USCF medicine professor John Balmes said in a press release.

“People should be sheltering in place as much as possible,” Balmes says. “Stay home with windows closed, ventilation turned to recirculate, and if possible, have a clean air room with a HEPA air purifying appliance.”

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For those noticing the smoky skies from the other side of the country, you probably don’t need to stress as much about air quality, as the smoke hovers somewhere around 20,000 to 30,000 feet above the ground which won’t dramatically impact the air we breathe.

But if you’re feeling nervous about air quality, especially if you live near where the fires are raging, it’s best to avoid the ickiness that comes along with smoky air. And with COVID-19 still complicating things, it’s probably best to hole up inside your home for the time being and wear a mask when needed.

Sara Kiley Watson

Sara Kiley WatsonSara Kiley Watson is an assistant editor at PopSci. Her work has also been featured in NPR and Business Insider. Contact the author here.