Poor Berkeley air quality from wildfires could improve by Monday

Smoke from multiple Northern California wildfires is mixing with the marine layer in the Bay Area, creating thick smog and blocking the sun. An air quality advisory is in effect in Alameda County.

smoky skies and a red sun
Smoke from Northern California wildfires was giving the sun a red tinge in South Berkeley on Sept. 11, 2020. Photo: Supriya Yelimeli

Heavy smoke and fog in Berkeley and the Bay Area will likely last through the weekend and the air quality is expected to be very unhealthy until the smoke clears.

Alameda County issued an air quality alert at 10:12 a.m. Friday, advising all populations to stay inside, and a record-setting Spare the Air alert has been extended to its 28 day through Monday Sept. 14.

The Bay Area Air Quality Management District’s monitor at Berkeley’s Aquatic Park registered in the “purple” range on Friday morning, with grey skies impacted by the August Complex fire in Mendocino and Northern California counties – now the largest wildfire in state history at 471,000 acres – and the North Complex or “Bear Fire” in Butte, Plumas and Yuba counties, which exploded in size earlier this week.

Wind speeds have dropped and both fires are burning at a slower rate as of Friday, Sept. 11, according to the National Weather Service, but now gravity has taken over and brought the smoke down to mix with marine fog in the Bay Area, creating a thick layer of smog.

This means the skies no longer have an apocalyptic red tinge like they did earlier in the week, but the temporary air quality relief is gone too.

This smog is blocking out nearly 80% of the sun’s energy and preventing the marine layer from melting away, and the NWS has issued a dense fog advisory for the entire Bay Area lasting through noon Friday.

“Add a compressing fog with descending smoke, and that’s a recipe for terrible air quality and poor visibility,” said NWS meteorologist Drew Peterson.

The weather forecast for the coming days, especially Saturday, is “low confidence” because the smoke is interfering with several of the nearly 30 models the NWS uses to predict weather.

“[The weekend] will probably be bad but we don’t know how bad. It’s a very very tough forecast.” — Drew Peterson, meteorologist

There’s a storm system coming into the Bay Area on Sunday that could increase wind speeds and push away some of the smoke, and residents may see skies clear up as soon as Saturday, but air quality on the ground level could be impacted until the beginning of next week.

“It’ll probably be bad but we don’t know how bad. It’s a very very tough forecast,” Peterson said about the weekend. “The wildfires and the smoke are creating their own weather. At least on the surface where we live, the computer models are not picking up on that.”

Temperatures were forecast to be in the high 80s earlier this week, for example, but the actual temperatures were in the high 50s to low 60s. Similar weather can be expected until the smoke clears up and the sun is able to shine through.

The new air system coming in from the ocean should be fresh and clean, Peterson said, but smoke from massive wildfires in Oregon may get mixed up depending on fire behavior.

Local services on Friday announced they would be shutting down due to the smoke, including Berkeley Unified School District’s “Ed Hub” for school supplies, and library drop-offs and pickups. The East Bay Regional Park District advised visitors to stay at home and said parks may close if conditions worsen even further. As of noon, the city has not released any information on an emergency shelter plan for homeless populations.

This developing story was updated after publication.

Supriya Yelimeli is Berkeleyside's general assignment reporter. Email: supriya@berkeleyside.com. Twitter: SupriyaYelimeli. Phone: (510) 585-8315.