1.
wildfire; forest fire; bushfire
An uncontrolled fire in a mountainous or forested area.
山火事 refers to an uncontrolled fire that spreads through mountainous or forested terrain, typically caused by drought, lightning, or human carelessness. It is the everyday word for wildfires and forest fires in Japanese, while the more formal equivalent is 森林火災.
Etymology
A compound of 山 (mountain) + 火事 (fire).