From the Document: "Wildfires are unplanned and unwanted fires. Wildfires can have some beneficial impacts on an ecosystem, but they often threaten homes and communities and force the evacuation of thousands of people. Wildfires are often caused by lightning strikes, and may also occur when a prescribed burn escapes control or through unauthorized human activities (deliberate or accidental). Over the last 10 years (2009-2018), wildfires have burned 7.0 million acres annually on average in the United States. In 2018, more than 58,000 wildfires burned 8.8 million acres and destroyed nearly 25,800 structures nationwide. More than 70% (18,130) of the structures destroyed were residences, and approximately 94% of the structures destroyed (17,130) were in a single state, California."
CRS In Focus, IF10732
Congressional Research Service: https://crsreports.congress.gov/