Weather in Northern California: High heat and a Spare the Air alert for wildfire smoke
In a word, weather in Northern California has been extreme.
And it isn’t stopping soon.
On Tuesday, amid a heat wave that has already triggered rolling blackouts and could threaten another energy shortage in the evening, air quality managers in the Sacramento area began issuing alerts for poor conditions triggered by fires.
Wildfire smoke triggered a Spare the Air day alert, the region’s second of 2020 and first this summer.
The Sacramento Metropolitan Air Quality Management District said the air quality index in the Woodland area has reached 160, considered unhealthy for the general population, according to an emailed alert sent early Tuesday afternoon.
Downtown Sacramento, Davis and Vacaville had AQI readings between 100 and 150 by midday, considered “unhealthy for sensitive groups,” such as those with asthma. Those air pollution levels could soon enter “unhealthy” territory as fires continue to burn and smoky conditions develop.
“(S)moke from fires in Glenn and Napa counties will impact the Sacramento region, enhancing ozone formation and increasing particle concentrations,” reads the forecast from SpareTheAir.com. “In addition, mostly sunny skies and hot temperatures will aid ozone production, and light winds through midday will limit pollutant dispersion.”
During a Spare the Air alert, people in the affected region are advised to limit outdoor time as much as possible — which was probably already a given, as Northern California continues to suffer through a sweltering and dangerous heat wave that began Friday and included weekend highs over 110 degrees.
Sacramento reached 99 degrees before 1 p.m. Tuesday, according to the National Weather Service, and is forecast to hit an afternoon high near 109 degrees, with a heat index of 112.
Fire crews in Glenn County gained full containment late in the weekend on the Elk Fire, a grass fire of over 700 acres, though its smoke impacts have persisted.
Napa County, meanwhile, is grappling with a still-uncontained complex of fires that were sparked by lightning amid powerful thunderstorms that swept through Northern California on Sunday and Monday.
Cal Fire’s Sonoma-Lake-Napa unit is battling three fires within that complex — the Gamble, Hennessey and 15-10 fires — combining for about 12,000 acres. They’re 0% contained, have destroyed three buildings and are threatening at least 200 more, Cal Fire officials say.
Smoke from the Napa County fires may continue to impact the region Wednesday as well, the air quality forecast says, especially if fire behavior increases.
Wildfire smoke causes an air pollutant known as particulate matter, or PM 2.5. The other main air pollutant is ozone. Local air quality officials say sunny skies and continuing above-average heat later this week, even as temperatures drop from nearly 110 to closer to 100 degrees, will continue to make ozone levels unhealthy for sensitive groups in the Sacramento area.
SpareTheAir.com, which is managed jointly by the Sacramento Metropolitan, El Dorado, Feather River, Placer and Yolo-Solano air districts, declared only six Spare the Air days in 2019 and is on only its second such day in 2020 after issuing the alert 17 or more times in each of 2016, 2017 and 2018.
Air officials issued alerts for the first 10 days of August 2018, due to the Mendocino Complex Fire, which sparked in late July and burned more than 700 square miles in parts of Mendocino, Lake, Colusa and Glenn counties.
