Zombie fires; also known as holdover fires, overwintering fires, and re-ignitions, are a potential risk when firefighters believe a wildfire has been extinguished, only to find that hidden hot spots remain. If it goes undetected, underground burning matter can be rekindled and cause another fire. In some cases, these hidden firebrands may exist for days or even months without being detected. Assigning liability for these types of fires can be done with the help of a California wildfire attorney.
What Is a Zombie Fire?
In California, a “zombie fire” is the revival of a fire that was previously thought to be dead or extinguished due to hidden burning matter that exists underground. Zombie fires most commonly burn in the lower layer of organic soils, peat and in tree root systems in the aftermath of wildfires.
They can exist on very little oxygen and emit low heat, making them extremely difficult to detect. Zombie fires originate from surface wildfires that, though firefighters may believe are 100-percent contained, are actually never fully extinguished. Beneath the ground or buried in the underbrush may be an ember that continues to smolder undetected. If the right conditions present themselves later, this underground fire can reignite and resurface.
What Conditions Lead to Zombie Fires?
Zombie fires are more common than many people realize. In 2025, the devastating Palisades Fire was a zombie fire. The Tunnel Fire in Oakland in 1991 was also a holdover fire. Certain conditions increase the odds of a zombie fire reigniting, such as:
- Dry weather. Especially dry weather can cause a firebrand to survive underground without going out for long periods of time.
- Winds. Strong winds, such as the Santa Ana winds, can provide oxygen to an underground fire that stokes and revives embers.
- Combustible fuel. California’s drought conditions can leech moisture from ground vegetation, creating better kindling for holdover fires to resurface.
- Hot summers. Studies have found a connection between hotter summers in the preceding year and zombie fires occurring the year following.
It is thought that climate change has increased the frequency and likelihood of zombie fires due to warmer and drier climates that make California’s peatlands which are filled with thick, carbon-rich and organic soils more flammable.
Can Zombie Fires Be Prevented?
Putting out a wildfire with water alone is often insufficient to douse deeper embers. It may be necessary to instead remove entire layers of soil and underbrush to clear away burning soil. Clearing the ground around buildings and homes can also help prevent firebrands from occurring and surviving. It can be difficult for firefighters and agencies such as CAL FIRE to detect and track active underground fires in the off-season.
Even in the winter in areas of California where it snows, however, firebrands can continue burning, as not enough moisture penetrates deep down to extinguish them. The embers may remain alive throughout winter and resurface during a dry spring.
Who Is Liable for a Zombie Fire?
If injuries or property damage are caused by a zombie fire in California, it can be difficult to get coverage from an insurance provider. The fact that the reignition of the fire was delayed can make it harder for investigators to identify the cause of the blaze – such as whether the wildfire was from a new incident or remnants of an older fire. There may also be questions of whether the original firefighters did enough to fully extinguish the first fire, potentially pointing to government liability for a rekindling. You may need help from a wildfire attorney to recover fair financial compensation from one or more parties for your fire-related losses.