It was clear from the start that something was wrong. By early May, the beginning of the western U.S. wildfire season, fires were breaking out at a rate one-third higher than normal. Flames had damaged or destroyed 12 homes near Minneapolis—the first residences lost to wildfires in the state of Minnesota in seven years. A small blaze in a national park southeast of Chicago jumped over a containment line and moved onto the grounds of a U.S. Steel plant—an area covered with green vegetation. Firefighters said it shouldn’t have burned.

It was scary. But it was only the beginning. The 2000 U.S. fire season turned out to be the worst in half a century—partly a result of warm and dry conditions accompanying the weather pattern La Niña. By late August, 4.9 million acres (2 million hectares) had burned nationwide, more than double the ten-year average. Federal troops had joined thousands of firefighters battling flames in 11 western states in an outbreak that wasn’t expected to end until the first snows of winter.

Wildfires are among nature’s most feared manifestations, especially for the growing number of people choosing to live in forested areas. Fueled by thick, dried-out underbrush and driven by wind, giant curtains of flame can leap across acres of land in minutes, leaving only charred rubble where there once were homes and human dreams.