A wildfire is any uncontrolled, non-structure fire that occurs in the wild land Synonyms such as wildland fire, forest fire, brush fire, vegetation fire, grass fire, peat fire, bushfire (in Australasia), and hill fire are commonly used. Causes are numerous and include lightning, human carelessness, slash-and-burn farming, arson, volcanic activity, pyroclastic clouds, and underground coal fires. Nine out of ten wildfires are reportedly caused by some human interaction.