Coastsiders awoke this morning to deep orange skies and dark that was lasting well into the day. Similar conditions were reported from the North Bay south throughout the region. Thick smoke high in the sky is the culprit.
Jan Null, certified consulting meteorologist for Golden Gate Weather Services, said the orange hue is caused by thick smoke high up that is filtering out most of the sun’s light. It’s similar to what happens during a sunset when the rays have farther to travel through the atmosphere. What’s left over, he said, is just the orange and yellow colors, casting the whole landscape in faded amber light.
“The smoke layers are about as thick as I’ve seen them,” said Null, who lives in Half Moon Bay. “It’s like twilight.”
Null said the smoke is from multiple area fires, primarily those from the north — even as far as Oregon, where new large wildfires kicked off on Tuesday. He said smoke from those fires looped offshore then came back over the Bay Area. Also combined overhead is smoke from fires burning across Northern California settling at different levels of the atmosphere and blanketing the entire Bay Area.
“It’s multiple sources at multiple layers,” Null said.
Air quality reports on the Coastside Wednesday morning showed indices in the 60s through 80s, which is within “moderate” range. It is not considered unhealthy for most, although air quality continues to be poor in the South Coast where the CZU August Lightning Complex fire continues to burn. That fire, the closest to Half Moon Bay, stands at 83 percent containment.
“(Air quality readings are) a little higher than normal, but for most people, it’s not even in the dangerous category,” Null said.
Null said he expects wind to come from the south in the next couple of days, pushing the smoke inland. With a heavy marine layer on the coast beginning to burn off, Null said the air conditions are likely to worsen today before gradually improving later this week.