Why wildfires started by humans, cars and power lines can be more destructive and harder to contain

(The Conversation is an independent and nonprofit source of news, analysis and commentary from academic experts.)

Virginia Iglesias, University of Colorado Boulder

(THE CONVERSATION) Wildfires are becoming increasingly destructive across the U.S. Research shows wildfires are up to four times larger and three times more frequent than they were in the 1980s and ‘90s, with some consuming hundreds of thousands of acres.

Lightning strikes are one cause, but the majority of wildfires that threaten communities are sparked by human activities.

Metal from cars or mowers dragging on the ground can spark fires. A broken power line started the deadly 2023 Maui fire that destroyed the town of Lahaina, Hawaii. California’s largest fire in 2024 started when a man pushed a burning car into a ravine near Chico. The fire destroyed more than 700 homes and buildings.

What makes these wildfires so destructive and difficult to contain?

The answer lies in...