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A hammer started the largest wildfire in California history, Cal Fire investigators say

One hammer. One swing. One spark. That’s all it took to start the largest wildfire in California history: the Mendocino Complex Fire.

A hammer striking a metal stake into the ground was determined to have been the cause of the largest wildfire in California history.

Cal Fire investigators reported their findings in a press release issued Thursday morning. Investigators did not identify who was swinging the hammer that sparked the fire and no charges have been filed.

Investigators said the fire began just to the north of the community of Upper Lake in Mendocino County. The conditions at the time were tinderbox-like, according to Cal Fire, with dry vegetation, strong wind, low humidity and high temperatures.


The Ranch Fire began just after noon on July 27, 2018. It would eventually merge with the River Fire and become known as the Mendocino Complex Fire. The fire was not declared inactive until November 7.

When it was all said and done, the fire burned more than 459,000 acres (approximately 720 square miles) and destroyed 157 homes. One firefighter was killed and three others were injured. No civilians were injured.

Read the full report on the cause of the fire by Cal Fire below.

WATCH MORE: Raw Video | Mendocino Complex Fires: Embedded

Scenes from the front lines as firefighters from Sacramento Metro Fire and Cal Fire battle the biggest blaze in California history. 

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