Central Arizona lies in what is known as the Transition Zone, mountainous terrain that is bordered by the dry Colorado Plateau to the north and the wetter Basin and Range Province to the south. It borrows characteristics from both of those landscapes: steep terrain and spur ridges alternating with flat valleys. The dominant plant types are juniper, turbinella oak, catclaw acacia, and manzanita. The combination of high ridges and level valleys makes the weather across the terrain highly local and variable. Conditions can change quickly in a relatively small area.
Every summer, usually in late June, a change occurs in the weather over central Arizona. Wet, colder air moves up from Mexico and pushes out the warmer, drier air that’s lain over the land all spring. In that meeting of cold and warm air, thunderstorms form, and as they get bigger they draw in the heat that’s been building up over the early summer. Then they go roaming over the high desert, dropping rain. In terms of wind, thunderstorms produce a range of effects: microbursts, gust fronts, outflows.
Every part of the country gets thunderstorms, but in the Southwest, they have a special significance: They can turn a gentle, meandering blaze into a blowtorch.
A storm during monsoon season is a double-edged sword, either helpful or hurtful depending on one factor: moisture. A wet thunderstorm can bring pounding rains, which can cool off fires or even put them out completely. But a dry thunderstorm pushes strong, unstable winds that can make a fire much hotter and faster moving. Some dry thunderstorms actually produce rain, but the air in the Southwest is so parched that the rain evaporates even before it hits the ground.
On June 28, 2013, an early-summer thunderstorm formed near a town called Yarnell, about thirty miles southwest of Prescott. This was the first big thunderstorm of the season, and the wet Mexican winds hadn’t fully occupied the terrain. There was little moisture for the winds to pick up. And much of the moisture the thunderstorm was carrying was in the form of ice crystals.
In the jostling streams of hot and cold air, the crystals collided. Electrons were sheared away from the ice molecules. They formed an intense electrical field, with thousands of volts per inch. Current began to flow. In the process, the surface of the earth became positively charged. When a filament of negatively charged particles intersects with a high point on the earth’s surface, the air heats to fifty thousand degrees Fahrenheit, five times hotter than the sun. Lightning flashes down to the dry terrain.
In the towns of central Arizona, things were tinder dry that summer. In Yarnell, the last good rain had been on March 7, and there’d been a light shower in early April that dropped a tenth of an inch of rain on the town and the surrounding hills, which was quickly sucked up by the oak roots and the cacti. The National Climatic Data Center, which monitors weather associated with drought, reported that there was “an abnormally dry fuel bed” in the area around the town that spring. A state agency, the Southwest Coordination Center—which has a Predictive Services section that attempts to pinpoint wildfire conditions in different localities—issued an advisory for the Yarnell area. Tucked into the bulletin was a section called “Concerns to Firefighters and the Public.” It listed four predictions for the coming fire season:
1. Surface fire will quickly transition to crown fire and only requires low to moderate surface fire intensity to transition.
2. Active/running crown fire has produced long-range spotting up to one mile under the influence of an unstable atmosphere.
3. Active fire behavior can extend well into night and early morning hours even with moderate relative humidity recovery.
4. Thunderstorm activity will create a mosaic pattern of surface fuel moistures[;] surface fire intensity and fire behavior may change abruptly when fires cross these boundaries of moist and dry surface fuels.
The predictions would all prove accurate. Points one and four would become especially important.
The conditions foreseen by the coordination center were confirmed on the ground. By May 17, a captain with the Yarnell Fire Department reported that the “danger of wildfire in the Yarnell area reached the maximum level (Extreme)… The scrub oaks, pine trees, untamed shrubs and dry grasses are all perfect fuels for a wildfire.”
There was no rain at all in May or June. In late June, the calculated probability of ignition for Yarnell and the surrounding area was measured at 60 percent for shaded areas (of which there were few) and 90 percent for unshaded areas.
Residents of the town had watched the huge mushroom smoke cloud from the Doce Fire in Prescott in mid-June and wondered if their decades-long run of good luck was over. Smoke on the horizon means something different than it did in frontier days. Then it meant a possible Indian raid. Now it means wildfire.
The thunderstorms arrived over Yarnell on June 28. On a ridge west of Yarnell, a flash of lightning hit a patch of rocky terrain at 5:36 p.m. The point of contact was probably a tall stand of manzanita or a juniper bush. The strike ignited the scrub oak, and flames sprouted across the ridge. But winds were mild and the fire only managed to sputter across half an acre that day.
When local residents called in reports of smoke, an Air Attack plane was sent out to spot the fire. After being unable to find it, the pilot finally radioed back that the flames were located in a boulder field on a west-facing slope, inaccessible to vehicles, and they were barely smoking.
It was a typical Arizona high desert wildfire. Hilly terrain at between 4,500 and 6,000 feet. Juniper, scrub oak, some pine. Very dry conditions. Public land, managed by the Bureau of Land Management, or BLM, which oversees 264 million acres of territory in the United States.
Our bread and butter, you might say. That day, June 28, there were thirty-seven active fires in Arizona, and Yarnell was one of the smaller ones. The land across the state was bone dry, aching to burn.
For the first day, Yarnell was a nothing fire. Spread potential was marked down as “minimal.” But on the second day, June 29, the fire began to grow, pushed by stronger winds. Two single-engine air tankers (or SEATs) arrived over the scene midmorning and dropped four loads of fire retardant on the blaze.
Just before eleven a.m., a helicopter from the BLM ferried in the first contingent of firefighters to battle the blaze. Six of the men were from the Arizona Department of Corrections—prison firefighters—and one was a “helitack” (short for helicopter attack firefighter). The men were dropped about a quarter mile from the ridge and began cutting fire line to contain the blaze.
The retardant penned the flames in on the western and southern flanks. A stone ridge was holding the fire in on the north and an old two-track road formed a natural barrier on the east. By that afternoon, the fire had grown to two acres, but it was still contained in its natural and manmade box. That afternoon, fire officials released the two SEAT aircraft, as well as two fire engines, so they could go fight other fires.
The typical afternoon breezes that bring relief to Arizonians arrived and the fire grew again. Officials now requested that the two SEATs return, along with an Air Attack plane to do recon and direct other firefighting aircraft. They got one SEAT; the other was held back for other fires that might spring up across Arizona.
The weather forecast for that day was grim. The temperature was expected to reach 105 degrees and the relative humidity was headed toward a dry, but not atypical, 11 percent. Perhaps most ominously, the National Weather Service issued a report about a storm cell developing to the northeast of Yarnell. A thunderstorm that might push toward Yarnell was developing. Storms mean wind, and wind is often the great variable in just how dynamic a fire can get.
Winds from the west-southwest continued to stoke the flames higher. The fire jumped the two-track road and began rolling east. The blaze had now broken containment and was ranging through terrain officials had originally thought beyond its reach. Thirteen firefighters hopped in their vehicles and zoomed up the two-track road to attack the “slop-over.” They dug a fire line as the flames roared in their ears. They knew that most of the buildings and people threatened by the fire lay to their east, so they worked furiously to stop the fire moving in that direction. By five thirty p.m., one of the Department of Corrections crews had run out of chainsaw gas, which cut their effectiveness drastically.
The fire was getting bigger and hotter. Its “operational complexity and tempo continue[d] to escalate,” according to a report from the Yarnell Hill Fire Serious Accident Investigation. Fire officials requested a large air tanker (LAT) and a Type 1 heavy helitanker, both of which carry more retardant than the single-engine aircraft. But at 5:42 p.m., the requested LAT and the helitanker canceled their runs; winds were too high along their flight paths. There was another option: a VLAT, or very large air tanker, a turbofan DC-10 that’s been converted to a tanker. These enormous planes can carry 11,400 gallons of rust-red retardant in belly-mounted tanks and release their entire load in eight seconds.
There are only two active VLATs in the entire country. Luckily, one of them was stationed in Albuquerque—just 450 miles from Yarnell—and the weather was good for takeoff. But there were other things to consider: The VLAT is expensive, costing around $57,000 for every load of retardant, which means it’s usually reserved for large fires. Yarnell, though uncontained, was still categorized as a small blaze. There was also a concern that terrain around Yarnell was too steep for the VLAT to be effective. With darkness approaching (tankers don’t fly after nightfall), the decision was made not to bring in the VLAT. The stated reason was “fire conditions.”
Late in the afternoon, the fire continued to outrun its boundaries. The small SEATs were still dropping retardant, but the scale of the fire had grown beyond their capabilities. The temperature at 5:24 p.m. was 101 degrees, with relative humidity at 12 percent and sustained winds of 10 mph, gusting to 20. The fire was eating through the chaparral at 100 to 200 yards per hour, with flame lengths between 10 and 20 feet.
The incident commander working Yarnell knew that if they didn’t stop the fire by nightfall, it could make a run in the morning and be in position to burn houses, even entire towns. The flames were now a mile from a small town called Peeples Valley and 2.5 miles from Yarnell. There were people there, horses, double-wide trailers, shops, government offices, homes. These weren’t the mansions in the hills that hotshots are often sent out to protect. They were the homes of working-class people, retirees, ex-servicemen on modest incomes, people who’d drifted out to the desert and found it to their liking. Ordinary Americans.
At 5:48 p.m., the Incident Commander in charge of the fire reported that it represented a threat to Yarnell and Peeples Valley in the approaching 24 to 48 hours.
Dusk came on. The horizon was lit by layers of purple and luminescent gray. There was mixed news that evening. The storm cell that the National Weather Service had spotted was fading; its winds wouldn’t threaten Yarnell. That was a relief to anyone who knows how wildfires behave.
But the fire continued its pattern of exceeding the expectations of the men and women attempting to control it. At 7:38 p.m., it had spread to one hundred acres, which meant that in twelve hours, it had grown fifty times larger. It was stubborn. It was seeking a breakout.
All night, fire officials called in bulldozers, fire engines, structure crews, and aircraft for the morning attack. The residents of Yarnell watched the flames glowing in the darkness that night. They had to level their eyes up slightly to see them. The hills blended with the darkness of the skies so that it appeared that the fire was floating above their heads. The flames were an enormous red-orange scar in the night sky.
Many residents had never seen a fire this big this close to their homes. Their hope was that the flames would “lay down”—that is, subside—during the night. They prayed for the winds to lessen. The 911 line was busy with calls.
By 10:00 p.m., a fire official called the Yavapai County Sheriff’s Office and told him to be ready to give local residents the evacuation orders. These are known as “reverse 911 calls.” There are no sirens or other means of emergency notification in Yarnell. If residents didn’t hear the phone or get the email, they wouldn’t know when the evacuation had begun.
Just before midnight, a supervisor jumped in his truck and went scouting along the back roads of Yarnell, surveying the town’s defenses. What he found were yards filled with trees right up to the siding, lots overgrown with shrubs and pine, roofs overhung with branches of dry pine. There hadn’t been a big fire in the area since 1966. Perhaps people had gotten to thinking one was never coming. Many of the houses the supervisor drove by were, from a firefighting point of view, completely indefensible.
If the fire reached Yarnell, the supervisor concluded, Yarnell would burn.
Some residents stayed up all night watching the progress of the flaming front. But others thought they might get lucky one more time. As one resident later wrote, these people “went to bed that night, assuming they were safe, as always.”