Containing wildfires—never mind extinguishing them—in parched and windy conditions can be monstrously difficult. Dry vegetation is rocket fuel for blazes and wind both feeds the flames and spreads the embers. “The winds are like pointing an air blower at a fireplace,” says Gershunov, “except it’s not contained and it’s on a much larger scale.”

LOS ANGELES -- Additional water tankers and scores of firefighters have arrived at the Los Angeles area ahead of fierce winds that were forecast to return and threaten the progress made so far on two massive infernos that have destroyed thousands of homes and killed at least 24 people.