SAN FRANCISCO (NewsNation Now) — Residents across the San Francisco Bay Area woke up to an orange glow in the sky and falling ash Wednesday as wildfires continue to rage across California.

The National Weather Service Bay Area said that larger particles of ash are falling to the ground, while smaller particles are suspended in the air, NewsNation affiliate KRON reported.

“Suspended smoke will descend closer to the surface and could lead to darker skies and worsening air quality today,” the weather agency announced on Twitter.

The National Weather Service reported that some of the ash falling is larger than the width of human hair, warning that residents should take precautions and wear masks.

Authorities are recommending that residents avoid exposure by staying inside with closed doors and windows until smoke levels subside.

Dr. Catherine Sonquist Forest, a professor at Stanford University’s medical school, told KRON that N95 masks can protect from breathing in smoke.

“The N95 mask will protect the person wearing it from incoming smoke but the valve still lets your breath out,” Forest said. “With COVID-19 virus, you can still infect someone if you’re talking, breathing, sneezing. So you need to wear your cloth mask over that. This is the way we protect one another.”

The Bay Area Air Quality Management District issued a Spare the Air alert through Wednesday, saying that air quality is expected to be unhealthy for sensitive groups across the region.

In California, winds stoked unprecedented numbers of fires that have forced rescues and evacuations. 

More than 14,000 firefighters are battling fires across the state. Two of the three largest blazes in state history are burning in the San Francisco Bay Area, though they are largely contained after burning for three weeks.