On August 15, the Hellroaring Fire began when a spark from a horseshoe ignited brush near an outfitter's camp in the Gallatin National Forest north of Yellowstone. At the same time, the Clover—Mist Fire in the northeast corner of the park pressed toward Cooke City and Silver Gate. On August 19, the Boise Interagency Fire Center called the U.S. Department of Defense and requested emergency firefighters because their firefighter reserve was empty. Also by this date, the fires in Yellowstone had spread to over 300,000 acres—not a good time to run short on firefighters. Yellowstone wasn't the only hotspot in the West, and it was competing for resources with other fires that were closer to large population centers.

August 20 was "Black Saturday." It was a good day for fire, but a bad day for firefighters—virtually all firefighting efforts were rendered ineffective because of the extreme and unpredictable winds. All eight fires made major runs, propelled by winds that gusted up to 80 mph and hurled fireballs nearly one mile ahead of the flames. Some firefighters fled from the flames that day; others could only stand by in a safe zone, watching as fire rumbled, then roared through the forest on its own wind, sucking oxygen from along the ground to sustain itself, then sometimes exploding into a 200—foot wall of flame. Enormous convection clouds punched up to 30,000 feet, fed by the fire's own wind. Firestorm winds toppled some trees before the fire consumed them. The Huck Fire began when a tree fell on a power line on the John D. Rockefeller, Jr. Memorial Parkway, closing travel between Grand Teton and Yellowstone national parks. The Flagg Ranch was evacuated, and Grant Village was evacuated for a second time. By the day's end, the fires had grown more than 50 percent and had torched an additional 165,000 acres.

-from "Chapter Four: Timeline of a Hot Summer"