Maps and other data released recently in an official investigation provide important clues to how the tragedy occurred.
The blaze started on June 28, the result of “dry” lightening strikes – lightening without rain – on an inaccessible mountain ridge near the central Arizona town of Yarnell. The fire grew slowly until the late afternoon of June 29 when winds, coming from the south, increased. By morning on the June 30, the fire had spread across about 500 acres.
Wind gusts continued out of the south-southwest throughout the day, picking up speed and driving the fire to the northeast. At about 3:50 p.m. on June 30, the wind shifted and began sending the fire toward the town of Yarnell. Soon after 4 p.m., Granite Mountain Hotshot Crew members left their position on a ridge in the “black” (land that had already burned), and headed southeast into a steep bowl-shaped area choked with dry trees, brush, and grasses that were “green” – unburned.
According to the investigation, the men appear to have been headed toward a ranch that had been cleared of plants and other fuels, in an effort to reengage the fire. They were within a few hundred feet of the ranch when, at 4:30 p.m., a thunderstorm from the north collapsed the column of hot air from the fire and sent flames roaring south. With the flames suddenly coming toward them, the men rushed to create a safe area, cutting trees and lighting a backfire. At 4:42 p.m., they radioed that they were deploying fire shelters – small tent-like structures made of fire resistant material – the last line of defense for a wildland firefighter.
It was not enough. No one survived the flames. Nineteen people died.
Perhaps more than any of the other material released in the investigation’s report, the “Wind vectors” map suggests why the fire was not survivable.
While a nearby weather station clocked wind gusts up to 43 mph, the topography of the land where the men were trapped increased wind speed to more than 52 mph. The fire was moving uphill while simultaneously being squeezed between the sides of the bowl formation. Temperatures reached an estimated 2000 degrees Fahrenheit, with flame lengths reaching 70 feet. Near the spot where the men died, investigators estimate that the front line of the fire moved 100 yards in just 19 seconds.
Why the men left the safety of the black is not known and will likely remain a mystery. Once they left it, however, and headed down into the bowl, the intensity, speed, and new direction of the fire made their deaths a near certainty.