UPDATE 9/12/26 10:35 P.M. – Lucas Fire grew to 4,008 acres near the rural Mendocino County community of Potter Valley and the Lake County line on Saturday, Cal Fire said.
San Francisco firefighters were dispatched to help battle the wildfire, which was 15% contained Saturday night. A Red Flag Warning was in effect through Monday afternoon due to strong winds and elevated fire weather conditions.
Evacuation orders and warnings were issued by Mendocino County and Lake County.
About 1,300 personnel were assigned to the fire and numerous firefighting air tankers from throughout the state were flying fire suppression missions, Cal Fire said.
A community meeting to update residents on the fire will be held at 6 p.m. Sunday at Running Creek Casino, 635 State Highway 20 in Upper Lake.
The meeting, to discuss fire activity, suppression efforts and evacuation considerations, will be livestreamed at https://youtube.com/live/aquabYADqB0?feature=share
It will include representatives from Cal Fire’s Sonoma-Lake-Napa Unit, the Lake County Sheriff’s Office, Mendocino National Forest, Lake County government officials and emergency management personnel.
The Mendocino National Forest ordered an emergency closure for a portion of the Upper Lake Ranger District. Campgrounds within the closure area include Middle Creek, Penny Pines, and Deer Valley.
State Highway 20 was closed at Bachelor Valley Road, Witter Springs Road and Saratoga Springs Road, Cal Fire said.
The fire was first reported at about 10 acres on Thursday morning. By Friday morning, it was more than 1,000 acres. The cause was under investigation.
UPDATE 9/12/26 12:22 P.M. – As of Saturday afternoon, the Lucas Fire has reached 3,846 acres and is 15% contained, according to Cal Fire.
UPDATE 9/12/26 7:45 A.M. – The Lucas Fire is currently 3,466 acres and is 15% contained.
UPDATE 3:00 P.M. – The Mendocino National Forest Supervisor’s Office issued an emergency closure for a section of the Upper Lake Ranger District on Mendocino National Forest in northern Lake County due to the Lucas Fire.
The closure covers all national forest roads, trails and campgrounds within a boundary running east along Forest Road 16N30 from Sam Alley Ridge, north along 16N01 and Elk Mountain Road (M1) and west along McCreary Glade Road (17N99) back to the forest boundary.
Campgrounds affected include Middle Creek, Penny Pines and Deer Valley. The following off-highway vehicle trails are closed: 01, 05A, 07, 10, and 15.
For the full forest alert, visit www.fs.usda.gov/.
UPDATE 9/11/26 2:41 P.M. – The Lucas Fire has been mapped to 3,476 acres by intelligence aircraft, with an inversion layer and smoky conditions hampering flight operations, according to Cal Fire. The fire remains at 5% contained.
Smoke from the fire may be visible in Lake County and surrounding communities, impacting air quality in the area. To check current air quality and wildfire smoke conditions, visit airnow.gov/wildfires.
A Red Flag Warning is in effect for Lake County from Saturday through Monday, as weather conditions can contribute to rapid fire growth.
Immediate evacuation orders remain in place for MNF-E016, MNF-E018, MNF-E019, UPP-E023, UPP-E025, UPP-E026, UPP-E027 and UPP-E030.
Evacuation warnings have been issued for the following: MNF-E012, MNF-E013, MNF-E015, MNF-E017, MNF-E021, UPP-E028, UPP-E031, UPP-E032, UPP-E035, UPP-E038, MEN-2UKV28 and MEN-2POT08.
To find out what zone you live in, visit mendoready.org or protect.genasys.com.
UPDATE 8:30 P.M. – The Lucas Fire has now spread to 1099 acres and is 5% contained as of Thursday night.
The fire is “burning in a remote location with difficult access,” according to Cal Fire.
Immediate evacuation orders are in place for MNF-E016, MNF-E018, MNF-E019, UPP-E023, UPP-E025, UPP-E026, UPP-E027 and UPP-E030.
The following areas are under evacuation warning: MNF-E017, MNF-E021, UPP-E028, UPP-E031, UPP-E032, UPP-E035, UPP-E038, MEN-2UKV28 and MEN-2POT08.
UPDATE 4:10 P.M. – The Lucas Fire has now spread to 400 acres and urgent evacuations are in place, according to Cal Fire.
The following areas are to evacuate immediately: MNF-E016, MNF-E018, UPP-E023.
Other areas under evacuation warning include MNF-E019, UPP-E025, UPP-E026, UPP-E027, UPP-E030, MEN-2UKV28 and MEN-2POT08.
The latest update states that Cal Fire “is in contact with the Mendocino National Forest as the fire approaches forest lands.”
UPDATE 3:57 P.M. – The Mendocino County Sheriff’s Office issued an evacuation order Thursday afternoon for the Potter Valley area, as a wildfire has spread to 200 acres.
The warning advised residents to be ready to evacuate at any moment, gather belongings, check on neighbors and leave early if possible.
UPDATE 3:25 P.M. – The Lucas Fire in Potter Valley has now spread to 200 acres with zero containment, according to Cal Fire.
The fire is burning in “steep terrain.”
UPDATE 3.15 P.M. — The blaze, dubbed the Lucas Fire, in Potter Valley has reached 40 acres with zero containment, according to Cal Fire.
MENDOCINO CO., 9/10/26 — A vegetation fire that began Thursday morning in Potter Valley reached 15 acres by the afternoon, according to Cal Fire.
Lucas Fire, began at 9:18 a.m. near the Lake and Mendocino county line in Potter Valley northeast of Ukiah and northwest of Clear Lake. The fire is about 3 miles northeast of state Route 20.
The fire is burning in a remote area in grass and oaks, Cal Fire said.
As of Thursday afternoon, the fire had zero containment. The cause of the fire is under investigation.
Starting off, calling this a vegetation fire was their first mistake. We have just evacuated from bachelor Valley after watching this Inferno creep across the ridge all day. I suspect Cal Fire did not give this fire the attention it needed early on.
Best luck to you and all affected. I have no specific info about the initial CalFire response, really. Speaking generally, t’s been a quiet fire season for them so far so I expect there’s absolutely loads of resources available. Also, with the recent heat, and given where we sit in the calendar, I really don’t expect they weren’t paying FULL attention. Finally, seeing and (ugh) feeling all that tropical moisture stream in lately, anybody with a clue was expecting lightning. That’s the likely ignition source.
As for “vegetation fire” – well,.that’s what it started in. It wasn’t started as a “vehicle fire”, it wasn’t started as a “structure fire”, etc. I believe that’s how that works – it gets classified like that, early on. It’s probably important for some work that needs to happen, but isn’t much known.
Anyway – again, best luck. I understand this is extraordinarily stressful. The upcoming forecast – moderate SW winds, then shifting to NW with cold front approach and passage – fairly well sucks. It could be much, much worse though!
I expect it’ll all be OK, this time anyway, with some hard, dirty, dangerous work. Pray for and be thankful for all the firefighters, including the aviators.
Thanks, Jimi!
I don’t understand how the letter designations (for example, MNF-EO16) work. These may work for firefighters for whom I’m eternally grateful. But for those of us trying to help/comfort family and friends they complicate an already stressful situation.
Thank you to all firefighters and pilots fighting this fire,us Potter valley people have PTSD from passed fires,and we are all great full for all you brave souls who fight these fires and do your best to keep us safe,thank God for you,You have a job that I know I couldn’t do,but thank you for your brave souls.
Anyone have a clue how this started?
Lightening probably
Probably not. “Approximately 95% of all wildfires in California are caused by human activity” (ref: CALFIRE).
Its under investigation. Still too early to start blaming “Global Warming.” Need to wait a bit until it gets larger.