Why the Bay Area sky is haze and smoke yellow?
Tuesday morning, the sky over the Bay Area gleamed oddly bright. Wildfire is visible in the weather – as has been the case for three weeks – but the sooty conditions were different from those of previous days.
Smoke and air quality in San Francisco and North Bay could not be even odorized, but in the far East Bay of Livermore, conditions were “hazardous,” and the quality of the air was decent to moderate.
What is happening? What is this Yellow hazy colour?
National weather service predictor Roger Gass said that wildfire smoke was more than 100 kilometres to the Bay Area from the fires in August Complex in Mendocino County. The weight of dirty air is well above the sea layer, which this morning moved inland from the Pacific.
“That’s the reason it doesn’t smell smokey but the sky is a different colour,” explained Gass. “This fire is farther away so the smoke is getting lofted into the atmosphere and lofted over us.”
Jan Null, the meteorologist with Golden Gate Weather Services, has added that the marine inverse layer is a barrier. This morning, Null said, “That’s why air quality isn’t too bad. “The smoke can not be mixed up by the inversion, and the smoke goes through us.”
Tuesdays are different from the last weeks if smoke is carried low in the atmosphere and almost touching the ground immediately within the borders of the Bay area. For weeks, the Bay Area had been smelling like a campfire.
The LNU Lightning Complex in the North Bay, the SCU Lightning Complex in the East Bay and the Woodward Fire in Marin County are now all nearly contained.
But though fires emit less smoke in the Bay Area, numerous bursts are spitting out soot and debris, in addition to the August Complex. A huge smoke pen from the fast-moving Creek Fire east of Fresno in the Sierra Nevada has been taken by satellite imagery. Gass said that smoke from the burn had no significant effect on Tuesday’s Bay Area but is expected to arrive in the area as the wind changes in the coming days.
“This varying pattern can take several days, in which the smoke blows around the city,” said Gass. “We see no evidence of on-shore flow driving it away. By the end of the week, we can receive more Westerly flow to help shoot out some smoke but it all plays a major role in how many fires are being burnt and how much is being done.
The Bay Area Air Quality Management District has a Spare the Air Alert in effect through Wednesday, which makes it illegal to burn wood or wood products.
For air quality updates visit AirNow.gov.