We’re entering an era of mega-fire

On July 9, 2016, two hitchhikers camping illegally on private land north of Nederland, Colorado, piled rocks onto a campfire that they hadn’t fully extinguished. Shortly after, wind (most likely) flamed the embers into a blaze. By 1:30 p.m., tentative puffs of smoke gathered above the ad hoc site, flanked by groves of dry aspen and conifer. The fire soon made a 40-acre run up a hill and across a ridge heavily populated with homes.