Thomas Fire (2017)
Ventura & Santa Barbara Counties, California · Dec 4, 2017 – Jan 12, 2018
Largest modern California wildfire at the timeAcres burned
281,893
Lives lost
2
Structures destroyed
1,063
Year
2017
Duration
~6 weeks
What happened
The Thomas Fire burned for over a month across Ventura and Santa Barbara counties in late 2017, becoming (briefly) the largest wildfire in modern California history. Its burn scar later triggered the deadly Montecito debris flows.
Cause
Power lines
Location
Ventura & Santa Barbara Counties, California
Key facts
- ▪Largest modern CA fire at the time
- ▪Burned for more than a month
- ▪Burn scar caused the 2018 Montecito mudslides
- ▪Driven by prolonged Santa Ana winds
Replay the Thomas Fire in the spread simulator
This centers the wildfire-spread simulator on the Thomas Fire’s documented ignition point and replays its conditions on 2017-12-04 — the day’s strongest wind, temperature, and humidity from the open-meteo historical archive (which set the fire-day fuel moisture) — run through the same Rothermel surface-fire model used across FireRisk. Press ▶ Simulate to watch how fire tends to move under those conditions.
⚠️ Educational reconstruction — not the real fire perimeter
This is a simplified model of how fire spreads under the 2017 conditions, not the Thomas Fire’s actual burned area, official progression, or a prediction of any current fire. It cannot account for real fuels, suppression, spotting, or how conditions changed hour to hour. For real-time fire information always follow Watch Duty, official agencies, and local authorities — and call 911 in an emergency.
Loading the 2017 fire-day conditions…
Reminder: an educational reconstruction of fire spread under the 2017 conditions — not the Thomas Fire’s actual perimeter, an official record, or a forecast. Modeled spread, direction, and timing are illustrative only. Never rely on it for any safety decision.
Aftermath & what changed
Weeks after containment, heavy rain on the Thomas Fire’s burn scar triggered the Montecito debris flows that killed 23 people — a stark lesson that wildfire risk doesn’t end when the fire is out.
Could your home survive a fire like the Thomas Fire?
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Related major fires
Thomas Fire FAQ
When was the Thomas Fire and where did it burn?
The Thomas Fire started Dec 4, 2017 in Ventura & Santa Barbara Counties, California, and was contained Jan 12, 2018.
How many acres did the Thomas Fire burn?
The Thomas Fire burned approximately 281,893 acres.
How many people died in the Thomas Fire?
Approximately 2 people died in the Thomas Fire.
What caused the Thomas Fire?
Power lines.
Figures are approximate and compiled from official agency reporting; totals for recent fires may still be revised. FireRisk.ai is an independent wildfire-risk service.