Air quality expected to worsen in Sacramento area, improve in Lake Tahoe as wind shifts
Air quality levels worsened Thursday in the Sacramento region, and the weekend forecast shows that smoke billowing from Northern California wildfires will continue to create unhealthy breathing conditions into early next week.
Air quality has been spotty for weeks with several wildfires burning and spewing smoke across Northern California, with areas around Lake Tahoe showing the worst levels of particulate matter in the country. But those areas are expected to see some improved air quality overnight as wind shifts, pushing smoke south.
The Sacramento area experienced a respite from the poor air quality earlier this week, but the forecast from the Sacramento Metropolitan Air Quality Management District shows “Unhealthy” air quality levels from Friday through Monday in Sacramento and Placer counties. The conditions will reach “Very Unhealthy” levels in El Dorado County over the weekend.
Breathing conditions were expected to be unhealthy for sensitive groups Friday in Sacramento County and expand to all groups Saturday.
Everyone should limit prolonged or heavy outdoor exertion during unhealthy conditions, and sensitive groups should avoid prolonged outdoor exertion, according to the air quality district. During very unhealthy conditions, people with heart and lung disease, older adults and children should avoid all outdoor physical activity, and everyone else should avoid prolonged or heavy outdoor exertion.
The Sacramento region had an Air Quality Index reading of 150 on Wednesday, which means it was unhealthy for sensitive groups, according to sparetheair.com. The index reading was expected to jump to over 200 AQI by the end of Thursday and on Friday.
The Caldor Fire, which had burned over 136,000 acres as of Thursday morning, will continue to produce smoke in El Dorado and Placer counties, as well as far-eastern portions of Sacramento County, according to the air quality district. Westerly to northwesterly winds in the afternoon will bring into the Sacramento region more smoke from other Northern California wildfires, which will keep air particle levels high.
Particle levels in Yolo and Solano Counties were expected to be “Unhealthy for Sensitive Groups” on Friday and Saturday, according to the air quality district.
Flames from the Caldor Fire continued to burn farther east and closer to the Lake Tahoe basin on Thursday as authorities expanded evacuations in the area and extend the eastern end of the now nearly 50-mile Highway 50 closure, which begins at Sly Park Road in Pollock Pines on the west end and stretches toward South Lake Tahoe.
In a smoke forecast released Thursday morning by Cal Fire and the U.S. Forest Service, a wind shift Thursday afternoon into the evening will push smoke south and southwest and “marginally” improve air quality in the Lake Tahoe Basin starting Thursday evening. Areas south of the Caldor Fire and west of the Sierra Crest, including portions of Amador, Calaveras and Tuolumne counties, will likely see air quality worsen overnight.
Those in Grass Valley, Placerville, and Auburn may see smoke linger a little longer and see less clearing Thursday afternoon as lighter wind and smoke from fires from the north moves south, according to the smoke forecast. On Friday morning, conditions may be “quite smoky” in the Sacramento Valley and foothills due to the combination of transported smoke from fires to the north and the Caldor Fire.
The National Weather Service on Thursday issued a red flag warning, in place 5 a.m. Friday to 11 a.m. Saturday for parts of the northern and central Sacramento Valley as well as the foothills. Northerly gusts could kick up to around 25 mph to 35 mph, the weather service says. The warning includes most of Shasta County and parts of Glenn, Colusa, Yuba, Sutter and Butte counties, as well as Shasta-Trinity National Forest.
The Bee’s Mila Jasper contributed to this news report.
This story was originally published August 26, 2021 at 2:48 PM.
