Why does smoke turn the sky orange? Meteorologist explains science behind it

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ByMike Nicco KGO logo
Wednesday, September 9, 2020
Here's why wildfire smoke turns the sky orange
Why does wildfire smoke turn Bay Area skies orange? ABC7 News Meteorologist Mike Nicco explains the science behind it and why the eerie, dark skies shouldn't scare you.

SAN FRANCISCO (KGO) -- While stunning to even frightening, San Francisco's apocalyptic sky on Wednesday should not scare you.

LIVE VIDEO: ABC7 News cameras show apocalyptic orange skies across San Francisco Bay Area due to wildfire smoke

"Think of the atmosphere as a layer cake. On Wednesday, the Bay Area had a clean air cake with smoky frosting," ABC7 News Meteorologist Mike Nicco said.

The Bear Fire, part of the North Complex Fire in Butte County, exploded to more than 58,000 acres Tuesday night. The massive amounts of ash expelled into the air was trapped between 1500 to 10,000 feet.

PHOTOS: Dramatic photos capture orange, hazy skies seen all across San Francisco Bay Area

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San Francisco City Hall is shrouded in smoke from multiple wildfires burning in the Sierra Nevada and Coast Ranges of Northern California, Wednesday morning, Sept. 9, 2020.
AP Photo/Olga Rodriguez

The northeast winds that prompted the Red Flag Warning transported an ash saturated air mass directly over the Bay Area.

The ash reflects blue light but allows yellow, orange and red light pass through. As more ash gathered in the sky, it quickly changed from yellow, orange to almost red.

RELATED: Here's why the sky looks so orange, even though Bay Area air quality isn't terrible

Thankfully, our marine layer (sea breeze) kept pumping clean air below the ash to keep us relatively safe. The sea breeze strengthens Wednesday afternoon into the evening. At worst, only isolated areas on the northern and eastern fringes of the Bay Area could experience unhealthy air.

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