A fire requires three elements: oxygen, fuel, and a spark. Sometimes, the oxygen is Instagram, and the spark is a “gender reveal party.”

At the Eldorado Ranch Park on a late-summer Saturday, parents who wanted a spectacular way to learn and announce the sex of their in utero child set off a smoke bomb with colored smoke, according to the California Department of Forestry and Fire Protection. Immediately, dried vegetation ignited, and soon, more than 8,000 acres had caught fire.