Deep orange skies, ‘snowing’ ash as fire smoke swamps Bay Area

The skies around the Bay Area and other parts of Northern California took on a surreal glow Wednesday as smoke from a variety of fires shrouded the region.

From San Francisco to Yosemite, social media was filled with images of ominous red and orange skies and smoky air. It was so dark outside, many residents had interior lights flipped on even as midday approached.

The National Weather Service explained the conditions this way: “As the winds weaken aloft, gravity will take over as the primary vertical transport of the smoke. Suspended smoke will descend closer to the surface and could lead to darker skies and worsening air quality today.”

California

Photos: Surreal orange skies as wildfire smoke blocks sun in Bay Area

The skies around the Bay Area and other parts of Northern California took on an eerie glow as smoke from several fires enveloped the region.

Sept. 9, 2020

The skies were so dark that one utility worker in Mountain View had his truck headlights turned on as he worked on a fire hydrant Wednesday morning.
“The real problem is the ash falling from the sky,” said Fabian Rios, who was wearing a surgical mask as he worked on the hydrant. “I am just getting covered.”

UCLA climate scientist Daniel Swain said the fire smoke was blocking the sun to a significant degree.

“Extremely dense & tall smoke plumes from numerous large wildfires, some of which have been generating nocturnal pyrocumulunimbus clouds (“fire thunderstorms”), are almost completely blocking out the sun across some portions of Northern California this morning,” he wrote on Twitter.

Air quality was unhealthy for large swaths of the Central Valley and the northern coast of California on Wednesday, according to AirNow.gov.

Officials warned residents to stay indoors when they smelled the odor of smoke.

In the Bay Area, air quality conditions remained moderate, as — despite the dim, reddish skies — the smoke still remained mostly higher up in the atmosphere. But officials warned it could settle down to the ground level.

“If the smell of smoke is present or visible, it is important that Bay Area residents protect their health by avoiding exposure. If possible, stay inside with windows and doors closed until smoke levels subside,” the Bay Area AQMD said in a statement.

The agency tweeted an explanation for Wednesday’s orange- and red-hued skies, saying they’re “a result of wildfire smoke in the air. Strong winds over the past few days transported ash from fires in northern California and the Sierra Nevada into the region. These smoke particles scatter blue light & only allow yellow-orange-red light to reach the surface, causing skies to look orange. If smoke becomes too thick in a certain area, most of the light will be scattered & absorbed before reaching the surface, which may cause dark skies.”

The National Weather Service office for the Bay Area said there was an “unprecedented amount of smoke in the atmosphere as a record number of acres burn across California & the West. From space, you can’t even see @KarlTheFog & the marine layer as the smoke extends well out over the Pacific.”

Snapshots of a darkened, orange Bay Area proliferated on social media: San Francisco’s landmark TransAmerica Pyramid pointing into a sinister orange haze; streetlights turned on in front of the iconic Ferry Building on the city’s waterfront; a dark orange mist obliterating from view the Golden Gate Bridge’s towers.

“The day the sun gave up on 2020…” said one person’s tweet of a video in Tiburon.

“The sun has been up for about an hour now. We should have a sky filled with bright sunshine. It’s so dark out,” tweeted Drew Tuma, a meteorologist for KGO-TV.

The Bay Area is in the midst of its longest stretch of “Spare the Air” days — with its 23rd consecutive day on Wednesday — in which regional air quality officials forecast unhealthy air quality conditions.

The Bay Area AQMD has been issuing Spare the Air alerts since 1991. The previous longest consecutive stretch of such days was a 14-day period in 2018 as the Camp fire tore through the town of Paradise, becoming the deadliest and most destructive fire in modern California history, killing 85 and destroying more than 18,000 structures.

The Spare the Air alerts are forecast to continue at least through Friday.

As dangerous fire weather conditions continued Wednesday, red flag warnings were expected to remain in effect through Wednesday afternoon for large swaths of the Central Valley and Sierra Nevada.

“Humidity values will fall back into the single digits and teens this afternoon. These conditions will continue to impact current wildfires, and extreme caution should be taken to prevent starting additional fires,” the National Weather Service said.

Many Bay Area residents have kept “go bags” with documents, pictures and other valuable items close at hand in case they have to evacuate. A number have purchased generators in expectation that Pacific Gas & Electric will shut off power when the winds pick up, and some residents said they’d stocked up on fans and air-purifying machines.

Staff writer Maura Dolan contributed to this report.