Forest Service Announces Cause of 2020 Creek Fire

Release Date: 

Contact(s): Alex Olow

Pyro cumulus Cloud over the Creek Fire

CLOVIS, Calif. — The Forest Service announced the results of the investigation into the cause of the Creek Fire, a wildfire that began on September 4, 2020, and burned approximately 379,895 acres, destroyed 853 structures, and damaged an additional 64 structures on the Sierra National Forest below Big Creek. 

Despite an exhaustive investigation, the cause of the fire is officially categorized as “undetermined.” Fire investigators determined that the most probable cause was a lightning strike. Possible causes that were not excluded were deliberately and unlawfully setting fire to property (arson/incendiary) and smoking activities, such as tobacco. An “undetermined” status is not uncommon given the complexities involved. 

The investigation was able to exclude some potential causes that were fully considered, including equipment use, escaped campfire, debris burning, hazardous fuels reduction burning, railroad operations, activities by children, and the cause categories falling under miscellaneous (powerlines, fireworks, cutting, welding, grinding, firearms use, blasting, structures, glass reflection/refraction, spontaneous combustion, and flare stacks/fire pits). There were no illegal marijuana grow sites nearby, so that also was excluded as a possible cause.

“We all want to know a definitive cause to what started the devastating Creek Fire last year,” said Dean Gould, Forest Supervisor of the Sierra National Forest. “Investigators spent countless hours hiking rugged terrain to determine the cause, interviewed numerous leads, and eliminated multiple potential causes. In the end, lightning remains as the probable cause.” 

The Creek Fire was declared contained on December 24, 2020.  

“I want to thank the investigation team who spent hundreds of hours to try to determine the cause of the Creek Fire, as well as the public for their patience and understanding during this comprehensive investigation,” Gould added. “Future leads or information related to the cause of the Creek Fire may result in a change of the conclusion. At this point, the case is considered closed, pending further leads.”


Note: An important clarification is that at the local (Forest) level, the “InFORM” interagency fire reporting system allows for the cause of a fire to be entered as “Undetermined.”  However, once the reporting statistics are consolidated nationally, the system reduces potential causes to either “Human” or “Natural,” with any “Undetermined” causes defaulting to “Human.” The official cause of the 2020 Creek Fire, however, is undetermined.