Meteorologists on Wednesday were alarmed by the rapid overnight growth of the Bear Fire, which approached Lake Oroville and got unsettlingly close to where the town of Paradise was devastated by the Camp Fire.
The governor and others have also warned that some of the biggest fires that have been fought by fire crews for weeks should not be underestimated.
[Track the biggest fires in California, Oregon and Washington here.]
What should I know about air quality?
For millions of Californians fortunate enough to be outside the direct path of the flames, air quality is a major concern. One look out the window in the Bay Area on Wednesday morning yielded a pretty clear indication that things were not normal.
Beyond that, you can check AirNow, a website and app run by the Environmental Protection Agency, for the Air Quality Index. Anything above 100 is bad for sensitive groups — which includes even more people than usual, in light of the pandemic. Experts have said that poor air quality could aggravate Covid-19 symptoms or make people cough more, making them more contagious if they are infected.
[Read more about the A.Q.I.]
We’ve heard from Bay Area residents who say they rely on PurpleAir, another website that uses data from its air quality sensors around the world.
If the air quality is poor in your area (and it is in much of California), you should try to stay indoors with the windows closed if possible. A high-efficiency air filter is helpful as well. Many Californians, though, have neither option, and must head out to work each day in low-paid essential jobs, often in farm fields.
Why is the sky orange?
According to the Bay Area Air District, the region’s air pollution control agency, the orange skies around San Francisco and in much of Oregon and Washington are the result of ash and smoke from fires, rising high and spread widely by strong winds. The smoke particles tend to scatter blue light from the sun, while allowing “yellow-orange-red light to reach the surface, causing skies to look orange,” the agency said on Twitter.