Lucas Fire Forces Evacuations Near Potter Valley After Rapid 400-Acre Run

A wildfire that began Thursday morning in the hills near Potter Valley grew from a small vegetation fire into a 400-acre incident in the space of a few hours, pushing evacuation orders into Lake County and putting nearby Mendocino County communities on alert.

The Lucas Fire was reported at about 9:18 a.m. on September 10 near the Lake County and Mendocino County line. Early estimates put it at roughly 10 to 15 acres. By mid-afternoon, the fire had climbed to 40 acres, then 200 acres, before CAL FIRE's evening incident report placed it at 400 acres and 0% containment.

The Lucas Fire Went From a Small Start to 400 Acres in Hours

The pace of Thursday's growth is the main reason the incident drew attention so quickly. CAL FIRE initially listed the fire at about 10 acres. Local reporting from the Potter Valley area later tracked the estimate through 15 acres, 40 acres and 200 acres as crews worked in steep country.

By 5:38 p.m., CAL FIRE's formal incident update listed the fire at 400 acres. The agency still reported 0% containment at that point.

CBS Sacramento reported that fire officials described a moderate rate of spread with long-range spotting and requested additional ground and air resources. Spotting matters in this terrain because burning material carried ahead of the main fire can start new pockets of fire beyond the most visible edge.

Lake County Evacuation Orders Expanded as the Fire Grew

The strongest public-safety impact is on the Lake County side of the incident. CAL FIRE's latest detailed report lists evacuation orders for eight zones:

• MNF-E016
• MNF-E018
• MNF-E019
• UPP-E023
• UPP-E025
• UPP-E026
• UPP-E027
• UPP-E030

Seven additional Lake County zones were listed under evacuation warnings: MNF-E017, MNF-E021, UPP-E028, UPP-E031, UPP-E032, UPP-E035 and UPP-E038.

On the Mendocino County side, the latest CAL FIRE report lists evacuation warnings for MEN-2POT08 and MEN-2UKV28.

Where Is the Lucas Fire?

The September Lucas Fire is burning near Potter Valley along the Mendocino-Lake county line, northeast of Ukiah and northwest of Clear Lake. Early local reporting placed the fire roughly three miles northeast of State Route 20.

The location can be confusing because there was another California wildfire named Lucas Fire in Monterey County in July 2026. That earlier incident burned near San Ardo and was contained at 50 acres. The current Potter Valley incident is a separate fire that began on September 10.

CAL FIRE lists the Mendocino Unit as the administrative unit for the current fire. Evacuation impacts, however, extend across the county line into Lake County.

Steep Terrain, Grass and Oak Complicate the Initial Attack

The Mendocino Voice reported that the fire was burning in steep terrain in grass and oak vegetation. That combination can make a relatively small ignition difficult to reach and hold, especially when crews need to work around slopes, limited access and new spot fires.

The first day also showed why acreage alone can lag behind conditions on the ground. The incident moved through several size estimates in a short period while aircraft and ground resources were being added. A final perimeter can differ from the numbers reported during active suppression because later mapping is more precise.

For residents, the important distinction is between fire size and evacuation status. A fire does not have to become a major multi-thousand-acre incident before law enforcement orders people out. Evacuations are based on expected fire movement, access, terrain and the time needed to move people safely.

Lake County Fairgrounds Opened as a Temporary Evacuation Point

CAL FIRE's evening update lists the Lake County Fairgrounds, Baldwin Pavilion, 401 Martin Street in Lakeport as the temporary evacuation point. The location was also listed as available for livestock evacuations.

People moving animals should follow current county instructions before traveling. Livestock capacity and access can change during a fast-moving wildfire, and emergency routes need to remain clear for apparatus and evacuees.

What Caused the Lucas Fire?

The cause remains under investigation. No official cause was listed in CAL FIRE's latest detailed update reviewed for this report.

The same report did not publish confirmed incident-wide totals for destroyed structures, damaged structures, civilian injuries, firefighter injuries or fatalities. Blank fields in an early wildfire report should not be read as proof that no damage occurred; those numbers may not be available while the incident is still developing.

Any confirmed cause or damage assessment should be treated as a separate update rather than inferred from scanner traffic or social-media posts.

Where to Follow the Lucas Fire Live

This news post is intentionally not a second live-status page. AllFirefighter's incident tracker already records the Lucas Fire's acreage and containment history from official wildfire feeds.

That separation is useful during a developing fire: this article preserves the story of the rapid first-day growth and evacuations, while the tracker can change as new official numbers arrive.

Sources and Official Information

• CAL FIRE — September 10 Lucas Fire incident update — 400 acres, 0% containment, evacuation zones and temporary evacuation point.
• CAL FIRE — Lucas Fire incident page — agency incident record and future status updates.
• The Mendocino Voice — first-day fire growth, terrain, vegetation and Potter Valley location.
• CBS Sacramento — fire behavior, resource response and evacuation reporting.