What It’s Like to Fight a Megafire

04 November 2021

Published by https://www.newyorker.com/

USA – Mike West began working with the Lassen Interagency Hotshot Crew in the summer of 2004, when he was twenty-one years old. On one of his early missions, the crew was dispatched to Arizona, where lightning had ignited fires in the mountain peaks of the Coronado National Forest. The crew members camped more than eighty-five hundred feet above sea level, amid ponderosa pines and Douglas firs, and joined other crews of hotshots—élite firefighters revered for their endurance and skill—in battling what became known as the Nuttall Fire. The Lassen crew’s job was containment. Along a ridge bordering the main fire, they started making what firefighters call a “handline,” removing trees, roots, and other fuels from a continuous strip of land. Beyond the handline, they ignited their own fires with drip torches, creating areas of blackened ground to starve the main fire. This process, known as backfiring, is one of the core strategies of wildfire suppression.

One morning, the crews hiked along a knifelike canyon ridge. They were heading into “the hole”—the area downhill from their escape route—to contain a small fire that had crossed the handline. The terrain was rocky and punishing; at many points, the slope dropped steeply away. While the hotshots worked, lookouts monitored the main fire, watching for shifts in the wind that might change its behavior or direction. Todd Wood, the assistant superintendent of the Flagstaff Hotshots, observed from a knob of rock facing across the canyon and down onto Nuttall Creek. Over the radio, the fire meteorologist reported a weather update. On a scale of one to six on the Haines Index—a measurement of both the changeability and the dryness of the air—they were heading into a Super Six.

At around 12:30 P.M., Wood turned to check on the handline, then swivelled back. Just seconds had passed, but now he saw a crown fire—a blaze igniting the forest canopy—on the opposite slope. Because hot air rises, fires usually move uphill faster than they do downhill. But Wood saw a fast-moving front of flames, about three hundred yards across, running down the hill toward the creek. Once it crossed, the fire would move uphill toward the hotshot crews. It was a “blowup”: a sudden increase in fire intensity, accompanied by violent convection. “Nobody saw it coming,” Wood later recalled.

West was sitting on the ground, eating his lunch.

“Hey, W.,” a friend said. “Look at that smoke column.”

West glanced up and saw a churning mass in the sky. Squad leaders ordered the firefighters to assemble their gear. To West, time seemed to stretch. “I was standing in line just thinking, Let’s go, let’s go, let’s go,” he said.

By the time the hotshots started to hike out of the hole, the fire was boiling up toward them from the canyon floor. They moved as fast as they could, crawling over boulders and pulling one another up rock faces. Chainsaws were passed back and forth as crew members grew tired of carrying them. West struggled to breathe. As people began to fall behind, his squad leader yelled, “Just go, just go. Pass ’em!”

The sound of a running crown fire is sometimes compared to the roar of a freight train or the thunder of heavy ocean surf. It reminded West of a waterfall, or an ongoing explosion. Between the crews and the fire lay a stretch of unburned fuels which wildland firefighters call “the green.” “The fear is that you have this active, loud, roaring fire, and you’re in the green, and you have nowhere to go, and it’s just, is this going to get me?” West said.

The crown fire raced uphill, torching the trees to their right. They watched as the flames reached the ridge in front of them, then flicked over the edge and stopped. It took the group of around forty hotshots half an hour to get out of the hole; at the top, West threw up. The firefighters rested around a small lake. They learned that two crews were still trapped below, and a pensive mood set in. West watched as Skycrane helicopters dropped water on the fire. Behind the choppers, the smoke had risen so high that it had combined with the atmosphere to become a pyrocumulus cloud—a dark column of ash, smoke, and water vapor twenty thousand feet tall. At the top of the formation, where the ambient air temperature dropped below freezing, the vapor froze to create a smooth white surface, like a meringue—a process called ice-capping. It was the first time West had seen it. Over their radios, the firefighters heard that eleven hotshots in the hole were deploying their fire shelters. The small tents, made of an aluminized cloth, were designed to protect occupants from temperatures as high as seventeen hundred degrees.

“This is really bad,” West said to his squad leader.

“Yep,” the man replied, tersely.

After several hours, the trapped firefighters emerged from the hole. No one had died, but one person was taken to the hospital. For West, the Nuttall Fire seemed like a close call—the kind of experience he hoped he’d never have again. He didn’t know that it was a harbinger of things to come.

West’s career as a hotshot coincided with a transformation in American wildland firefighting. In the years following the Nuttall Fire, wildfires increased in intensity and complexity. The new fires often seemed to resist control and could easily spread to a hundred thousand acres or more, costing millions of dollars to suppress. A group of scientists coined the term “megafire” to describe the phenomenon. Megafires now account for a growing proportion of the total area burned in America each year; climate scientists predict that the number of days conducive to such fires will increase by as much as fifty per cent by the middle of the century.

This past spring, I trained to become a wildland firefighter; in the summer, the Dixie Fire became the largest single fire in California’s history. While West was telling me about his ordeal in the Nuttall Fire, Dixie was threatening to force an evacuation of Susanville, West’s home town. I was embedded with a firefighting crew sixty-six miles south of Susanville. By digging handline and laying hose, we were trying to contain an edge of Dixie’s monstrous perimeter, which would soon grow to encompass nearly a million acres.

Today’s largest fires behave in surprising ways. In the late nineteen-nineties, a few scientists began inspecting satellite images of unusual clouds over Australia and elsewhere; the meteorologist Michael Fromm speculated that they could be connected to the convective force of giant wildfires below them. Eventually, the researchers confirmed that particularly powerful wildfires could cause not just pyrocumulus clouds but vast firestorms called pyrocumulonimbus columns. Created by the flames at ground level, the columns are tall enough to generate lightning, and their air currents are so strong that they can punch particles of smoke into the stratosphere, where commercial jets typically cruise. “There were some who literally laughed when we tried to tell them what we thought was going on,” Fromm told me. Skeptics believed that “if you saw aerosols in the stratosphere it had to be a volcano.”

Since then, pyrocumulonimbus columns, which fire scientists call pyroCbs, have been observed with increasing frequency. In 2003, wildfires in Canberra, Australia, created a pyroCb with enough energy to spawn the first documented fire tornado—a Category F2, with wind speeds of more than a hundred and thirteen miles per hour. In the twenty-tens, scientists identified pyroCbs in western Russia, Europe, Africa, and South America, and the formations have now been seen above the Arctic Circle. Two years ago, during Australia’s Black Summer wildfires, eighteen pyroCbs emerged in a single week, causing giant plumes of smoke to spread across the Southern Hemisphere; one such plume grew to be six hundred and twenty miles wide. “It shocked us all,” Fromm said.

When the towering formations tumble to earth, they release massive energy in the form of downdrafts. These high-speed winds are dangerous for firefighters; as Crystal Kolden, a professor of fire science at the University of California, Merced, told me, they “are very well known as extreme-fire-behavior generators.” Fed by gusts and fuels, megafires can swallow tens of thousands of acres in hours, overtaking firefighters with little warning. Their smoke shades large areas of the earth, unsettling the usual patterns of night and day and creating sudden wind shifts.

Wildland firefighting has always been risky, but the risks have grown along with the fires. Between 1910 and 1996, the National Wildfire Coordinating Group counted six hundred and ninety-nine on-duty deaths among wildland firefighters; according to the Federal Emergency Management Agency, in the past thirty years, more than five hundred have died. Tom Lee, a Green Beret who deployed to Afghanistan nine times and worked as a wildland firefighter in 2018 and 2019, told me that fighting megafires was one of the most dangerous jobs he has ever done. “Fires are dynamic—they’re unpredictable,” he said. He likened the work to combat: “You can plan for every contingency, but there is always that unknown factor.”