Lucas Fire Triples to 3,476 Acres As Red Flag Warning Takes Effect Saturday

The Lucas Fire more than tripled in size Friday, reaching 3,476 acres along the Mendocino-Lake county line as fire crews worked to keep it away from more populated areas, and forecasters warned that critical fire weather arriving Saturday could fuel its continued spread.

Mendocino County Sheriff Matt Kendall, reached by phone on Friday afternoon, said the fire is moving away from Mendocino County. He said that only "one small portion" of it was ever in the county, describing open country with "no humans out there."

Kendall said he offered mutual aide to the Lake County Sheriff's Office on Thursday, sending over four deputies to help with evacuations and that he and Lake County Sheriff Luke Bingham have been in touch throughout the day.

"We are battling with low relative humidity and the afternoon winds we always get in September," Kendall said. "It's going to be some work."

Intelligence aircraft mapped the fire at 3,476 acres Friday afternoon, up from 1,099 acres that morning. Containment stood at 5%. An inversion layer trapping smoke over the fire hampered flight operations for much of the day, but four Type 3 air tankers had returned to the fire by the afternoon, according to CAL FIRE's Sonoma-Lake-Napa Unit.

The National Weather Service in Eureka issued a red flag warning for all of Lake County, in effect from 10 a.m. Saturday to 2 a.m. Sunday. Forecasters expect northwest wind gusts of 20 to 30 mph, reaching 40 mph on higher ridges, with relative humidity falling to 20% to 30% — conditions under which fires already burning "will likely spread rapidly," the weather service said. The warning covers the county's northern, eastern, southern and western zones, including Gravelly Valley, Clearlake, Middletown, Cobb, Konocti and Lakeport.

The fire is burning between Elk Mountain Road, Bachelor Valley Road and the Mendocino National Forest, according to Ryan Isham, the operations section chief. "We want to keep that fire in its current size and location," Isham said, describing an attack that pairs aircraft with dozers, hand crews and engines building containment line wherever crews can reach it. Firefighters defended structures in Bachelor Valley overnight.

Evacuation orders remained in place for eight zones in Lake County — MNF-E016, MNF-E018 and MNF-E019, and UPP-E023, UPP-E025, UPP-E026, UPP-E027 and UPP-E030. Evacuation warnings widened to 10 Lake County zones, adding MNF-E012, MNF-E013 and MNF-E015 to MNF-E017, MNF-E021, UPP-E028, UPP-E031, UPP-E032, UPP-E035 and UPP-E038. In Mendocino County, warnings stayed in effect for two Potter Valley-area zones, MEN-2POT08 and MEN-2UKV28.

Crews set additional temporary closure points along Highway 20 at Bachelor Valley Road, Witter Springs Road and Saratoga Springs Road. The Lake County Fairgrounds in Lakeport opened as a temporary evacuation point, along with an animal evacuation shelter.

The fire started Thursday morning near the county line, southeast of Potter Valley and about three miles east of Highway 20, in the footprint of the 2018 Ranch Fire. It grew from 10 acres to 400 acres by late Thursday afternoon as afternoon winds pushed it east toward the Mendocino National Forest. Lightning was recorded in the area, and the cause remains under investigation.

Typo fixed "relative humidity" 4:54 p.m. September 11, 2026