Gusts, heat bring ‘critical’ fire risk back to Northern California. How windy will it get?
Hot, gusty conditions expected to arrive by midweek will bring dangerous wildfire weather conditions back to California after only a brief reprieve, according to the latest forecasts.
The National Weather Service has issued a fire weather watch, taking effect Wednesday morning for a large portion of Northern California: the northern half of the Sacramento Valley including the western edge of Sacramento County, most of the Sierra Nevada foothills and the majority of the Bay Area.
As of Tuesday morning, the NWS predicts north-to-south and east-to-west winds up to 25 mph and gusts up to 35 mph throughout the sprawling fire warning area, with stronger gusts than that possible at higher elevations.
Gusts, temperatures ranging from the upper 80s to 90s, low humidity and mostly dry vegetation will create “critical” wildfire risk across the region, the NWS says.
The fire weather watch is in place 5 a.m. Wednesday through 10 a.m. Friday. A fire watch is one level below a red flag warning, which is the agency’s highest alert for an imminent wildfire weather event. Many red flag warnings start as a fire weather watch, which is then upgraded within 24 hours or so of the anticipated winds.
Where are wildfires already burning?
The NWS warns that any new fires that pop up later this week are likely to spread rapidly.
On top of that, more than a dozen major wildfires are currently burning statewide, nearly all of which sparked from mid-August through late September and had intense growth fueled by wind events that have come on a near-weekly basis since then, according to fire and weather officials.
Crews have made great containment progress amid minimal fire activity across Northern California for about the past week, according to Cal Fire. Temperatures cooled and winds were mild last week, and very light precipitation fell in the northern reaches of the state over the weekend.
But this week’s gusts could potentially flare up flames and test containment lines, as has happened multiple times in the past three months of California’s record-setting wildfire season.
Three large wildfire incidents are currently burning in areas within the latest NWS advisory.
The North Complex, burning mainly in the foothills counties of Butte and Plumas, is 94% contained. It destroyed nearly 2,500 structures and killed 15 people after scorching nearly 320,000 acres, according to the U.S. Forest Service. All of the deaths and most of the destruction came in the West Zone of the fire — a section that had remained essentially dormant for weeks, after the fire ignited via lightning in mid-August, then erupted into communities north of Lake Oroville in an early September wind event.
Cal Fire, which took command for the West Zone of the North Complex, says that zone has been fully contained for a couple of weeks. The Forest Service continues mop-up efforts on the rest of the complex.
The million-acre August Complex, centered around Mendocino National Forest in Tehama County but impacting parts of six other neighboring counties, benefited from some of the light rainfall that sprinkled over the weekend. Moisture helped bring at least three of the complex’s four distinct zones down to “creeping and smoldering” activity, the Forest Service said in a Monday evening update. As a whole, the complex is 76% contained.
And the 67,500-acre Glass Fire in the North Bay area is 96% contained after sparking a little over two weeks ago, and burning down nearly 650 homes in Napa and Sonoma counties. Cal Fire said Monday evening that fire activity remains minimal, and most previously evacuated residents are able to return home.
The cause of the Glass Fire remains undetermined, but it spread explosively within its first 48 hours due to extremely gusty winds in late September.
How hot will it get in Sacramento and across Northern California?
The latest NWS forecasts predict Northern California will gradually warm up through the end of the week, and may then cool slightly this weekend.
Highs in the Sacramento Valley are expected to range from the mid-80s to mid-90s Tuesday through Friday. The foothills should stay mostly in the 80s but could touch 90.
Sacramento is forecast to be 90 degrees and sunny on Tuesday, then warm up 1 degree a day through Friday, which could hit 93. Saturday will be slightly cooler at around 89 degrees, and the cool-down is expected to continue Sunday with a forecast high of 84.
Friday’s anticipated high of 93 would be 15 degrees above normal for Sacramento in mid-October, and would come two degrees shy of an all-time record of 95 degrees set in 1961.
The capital city, like other parts of the valley, could see gusts exceed 25 mph. Peak winds are expected Wednesday.
Temperatures will stay cool in South Lake Tahoe, expected to stay in the mid-60s now through at least Sunday, NWS forecasts show.
Will PG&E shut off power?
About 50,000 Pacific Gas and Electric customers in portions of 21 Northern California counties could lose their electricity as early as Wednesday afternoon, in the latest series of the utility’s public safety power shutoffs to prevent new wildfires.
PG&E Corp. on Monday notified customers of the potential electricity shutdown due to fire weather. These conditions present an increased risk of damage to the utility’s electrical system, which has the potential to ignite fires in areas of dry vegetation, PG&E officials said in a news release.
The targeted areas for shutoffs include portions of Placer, El Dorado, Yuba, Nevada, Solano, Sonoma, Butte and Calaveras counties. The other counties are Alameda, Amador, Contra Costa, Lake, Monterey, Napa, Plumas, San Mateo, Santa Clara, Santa Cruz, Shasta, Sierra and Tehama.
As of Tuesday morning, PG&E has not announced a final decision on whether or where it will cut off power.
Climate change and California wildfires
Wildfires have always been part of life in California. The past four years have brought some of the most destructive and deadliest wildfires in the state’s modern history.
Nearly 180 people have lost their lives since 2017. More than 41,000 structures have been destroyed and nearly 7 million acres have burned. That’s roughly the size of Massachusetts.
So far this year, at least 31 people have died, according to Cal Fire.
Meanwhile, this year’s August was the hottest on record in California. A rare series of lightning storms sparked a series of fires, including the August Complex that has burned nearly 1 million acres, making it by far the largest wildfire in California’s recorded history.
The 2017 wildfire season occurred during the second-hottest year on record in California and included a devastating string of fires in October that killed 44 people and destroyed nearly 9,000 buildings in Napa, Lake, Sonoma, Mendocino, Butte and Solano counties.
The following year was the most destructive and deadliest for wildfires in the state’s history. It included the Camp Fire, which destroyed the town of Paradise and killed 85 people, and the enormous Mendocino Complex.
This story was originally published October 13, 2020 at 8:46 AM with the headline "Gusts, heat bring ‘critical’ fire risk back to Northern California. How windy will it get?."
