SAN FRANCISCO (CBS SF) -- Shifting winds pulled a large plume of smoke from the raging Caldor and Monument wildfires over the San Francisco Bay Area Friday, casting a haze over the area, triggering a Spare the Air alert, and forcing the cancellation of youth sports games.
The Monument Fire burning in Trinity County was at 157,557 acres and was 20 percent contained. The Caldor Fire, meanwhile, continued to rage near Lake Tahoe along Highway 50 and had grown to 143,951 acres.
Southwest winds have been fueling the flames advance near Kyburz and Strawberry, driving a thick layer of smoke over the Lake Tahoe basin.
Now those winds have shifted. The National Weather Service said dry northerly winds were pushing the plume westward and over the Bay Area.
Friday afternoon, schools in the East Bay -- including Pittsburg, Antioch Union, and Liberty -- cancelled all football games because of the poor air quality.
The unhealthy air was affecting people trying to go about their day in the East Bay suburb of Walnut Creek Friday.
"It's awful. I'm sick of it," said an Orinda Resident who gave her name as Jenny. "I'm thinking of moving actually, because you can't go outside all summer long. You can't even go on vacation anywhere. You can't let your dogs out, can't let your kids play outside. It's just too much."
The Bay Area Air Quality Management District on Thursday issued an air quality advisory for Friday and Saturday. Late Friday morning, the advisory was upgraded to a Spare the Air alert for both days.
Air quality is forecast to be "unhealthy for sensitive groups" on the Air Quality Index in most of the Bay Area with pockets of "unhealthy" air quality at higher altitudes.
Residents and visitors in South Lake Tahoe and Tahoe City have endured some of the nation's worst air pollution for several days, according to AirNow.gov, a partnership of federal, state and local air agencies.
Officials warned that air quality levels in El Dorado County are reaching extremely hazardous levels beyond the air quality index due to the Caldor Fire.
Parts of El Dorado County, like Camino, are seeing an AQI level of over 1300 early Friday afternoon.
County healthy officials note that an AQI of over 300 is already unhealthy for people with good health. People who have underlying conditions could be severely affected by such poor air quality levels that the county is seeing right now, officials say.
South of Tahoe, Rick Nelson and his wife, Diane, had planned to host a weekend wedding at Fallen Leaf Lake, where his daughter and her fiance had met. However, the smoke caused most of the community to leave. The sun was an eerie blood orange, and the floats and boats in the lake were obscured by haze Tuesday.
In the end, the Nelsons spent two days arranging to have the wedding moved from the glacial lake several hours southwest to the San Francisco Bay Area.
"Everybody's trying to make accommodations for the smoke. And I think it's becoming a reality for us, unfortunately," Diane Nelson said. "I just think that the smoke and the fires have gotten bigger, hotter and faster-moving."
The burning of wood, manufactured fire logs or any other solid fuel, both indoors and outdoors is prohibited during Spare the Air alerts.
"As wildfires continue to burn in California, conditions are changing very quickly," said Jack Broadbent, executive officer of the Air District. "Wildfire smoke is unpredictable. When wildfires are active, it's important to stay alert and check air quality conditions to protect your health from smoke."
Residents can keep track of the latest air quality readings at baaqmd.gov/highs or the AirNow Fire and Smoke Map at fire.airnow.gov. The independently run air monitoring website PurpleAir.com also provides localized air quality measurements.
To find out when a Spare the Air Alert is in effect, residents can sign up for text alerts by texting the word "START" to 817-57, register for email AirAlerts at sparetheair.org, call 1(800) HELP-AIR, download the Spare the Air App or connect with Spare the Air on Facebook or Twitter.
Temperatures will also be soaring over the next 72 hours. The weather service issued a heat advisory for Mendocino and Lake counties for Friday.
Locally in the Bay Area, triple digits were in the forecast for many inland areas including communities east of the Caldecott Tunnel.
The soaring temperatures and low humidity levels will also continue to suck moisture out of brush and trees in the drought-ravaged region, elevating the threat of fires.
"Warming and drying trend will rapidly dry out the fine fuels over the next 1-3 days with Energy Release Component values expected to slowly rise back towards the 97th percentile," the weather service said. "Hills will remain warm and dry with no night time humidity recovery through the weekend."
The Energy Release Component is used to measure the likelihood that an ember could spark a fire.
© Copyright 2021 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.
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