Every evening from late spring to early fall, two planes lift off from airports in the western United States and fly through the sunset, each headed for an active wildfire, and then another, and another. From 10,000 feet above ground, the pilots can spot the glow of a fire, and occasionally the smoke enters the cabin, burning the eyes and throat.
The pilots fly a straight line over the flames, then U-turn and fly back in an adjacent but overlapping path, like they're mowing a lawn. When fire activity is at its peak, it's not uncommon for the crew to map 30 fires in one night. The resulting aerial view of the country's most dangerous wildfires helps establish the edges of those fires and identify areas thick with flames, scattered fires and isolated hotspots.