Thorn

Thorn Fire Report - July 18, 2026

Fire Start, Size and Growth

Start Date/Time/Location: The Thorn Fire ignited at approximately 8:45 a.m. on Wednesday, July 15, 2026, near Buckthorn Trail and Clover Trail in the Live Oak Springs neighborhood of Boulevard in San Diego County.
Size and Containment: As of the morning of July 18, 2026, the fire has burned 1,234 acres and is 80% contained.
Fuels, Growth and Rate of Spread: Fueled by hot, dry conditions and a sweltering heat wave, the fast-moving flames initially spread south of Interstate 8 and north of Campo Road. Driven by warm winds, the fire spread at a moderate-to-dangerous rate, jumping the interstate about 90 minutes after ignition. The forward rate of spread was officially halted on Thursday, July 16.
Containment Efforts: Unified Command is led by the CAL FIRE San Diego Unit. Night-flying helicopters played a critical role in slowing the fire's spread by making continuous water drops, allowing ground crews to strengthen containment lines. Firefighters are currently engaged in active mop-up operations, targeting interior hot spots to secure control lines. Damage inspection teams are active on the ground, with assessments currently 65% complete.

Emergency Information

Evacuations and Sheltering:
Mandatory Evacuation Orders: Due to improving conditions, all evacuation orders for the Thorn Fire have been lifted as of July 18. Previously, orders were in place for zones on both sides of I-8, including SDC-2174, SDC-2175, SDC-2176, SDC-2331-A, SDC-2332, SDC-2333, SDC-2334, SDC-2241, SDC-2242, SDC-2243, and SDC-2244.
Evacuation Warnings: All evacuation warnings (previously affecting zones SDC-2117, SDC-2177, SDC-2245, SDC-2335, SDC-2408, and SDC-2410) have also been lifted.
Curfew: No curfews are currently reported for the area.
Evacuation Shelters and Information: The Temporary Evacuation Point that was previously open at the Golden Acorn Casino in Campo is now closed. While official estimates on the exact number of people impacted were not released, the orders primarily affected the rural populations of the Live Oak Springs and Boulevard communities.

Road and Infrastructure Closures:

• All road closures have been lifted. Interstate 8, which was previously closed in both directions between Ribbonwood and Crestwood, now has all lanes open in both directions.
• Ribbonwood Road, across from Roadrunner Lane, is also now open.
• Officials urge motorists to drive cautiously in the area and watch for emergency crews.

For more information, visit:

• CAL FIRE San Diego Unit Incidents
• San Diego County Emergency Site
• Caltrans District 11 Traffic Updates

Current Impact

Impacts:
Injuries and Fatalities: There have been no reported civilian or firefighter injuries or fatalities associated with the Thorn Fire.
Structures Impacted: Despite the fire's rapid initial spread and immediate threat to backcountry homes, no structural damage or destroyed buildings have been reported.
School and Business Closures: No widespread school or business closures are currently reported, though local traffic and detours significantly impacted the Live Oak Springs community during the height of the fire.
Notable Impacts: The fire temporarily jumped Interstate 8, causing significant traffic disruptions and leaving residents in the Live Oak Springs community with limited evacuation routes.

Safety Concerns:
Power Outages: No significant power outages have been reported in relation to this incident.
Water Safety: No specific water safety concerns have been reported.
Burn Bans: Standard summer fire restrictions and burn bans remain in effect for San Diego County due to extreme fire danger.
Air Quality: A smoke advisory was initially issued by the San Diego County Air Pollution Control District due to large plumes of smoke, but it has since been lifted. Residents are still advised to limit outdoor activity and stay indoors if they smell smoke.

Ongoing Outlook

Containment Projections: With the fire at 80% containment and the forward rate of spread stopped, there is a low probability of outward fire growth. Firefighters will remain on the scene to patrol, reinforce containment lines, and mop up remaining interior hot spots over the coming days to push toward full containment.
Weather and Wind Warnings: Extreme heat has persisted over the incident, with temperatures exceeding 100 degrees. Fire behavior analysts are closely monitoring an incoming monsoonal weather pattern, which is expected to bring an increased potential for dry lightning and thunderstorm development that could pose new challenges.

Cause and the Role of Weather and Climate

Cause: The cause of the Thorn Fire remains under investigation.
Weather and Climate: The fire was heavily influenced by extreme weather conditions, including a sweltering regional heat wave with temperatures soaring past 100 degrees, low relative humidity, and dry, warm winds. These climate-driven extremes created highly receptive fuels, allowing the fire to spread rapidly upon ignition. The ongoing threat of monsoonal moisture and potential dry lightning further highlights the role of volatile summer climate patterns in the region's fire activity.

For more information, visit:

• CAL FIRE Active Incidents
• San Diego County Sheriff's Department
• San Diego County Air Pollution Control District