The Big Burn, Chapter 10, "The Blowup"

A wind out of the American West that tumbles in roller-coaster fashion is known as a Palouser, a Sahaptin Indian word that sounds poetic . . .

Stirring to life in midday, the wind rustled the tawny heads of wheat and tall grass before jumping over the Snake River into Idaho and barreling north into the Nez Perce National Forest . . . When it ran into walls of ancient rock, the wind compacted and accelerated. Forcing its way upward, following the contours of the land, the racing wind hit the first fires in a mix of pines at lower elevations. These fires had been ignored by the Forest Service, left to burn out once the underbrush was consumed. The wind took the hot floor of the simmering forest and threw it into the air, where it lit the boughs of bigger ponderosas and white pines, which snapped off and also rode the force of upward acceleration. Pine sap heated quickly and hissed as it reached a boiling point. Every headwall, every dead end of a a canyon, every narrow valley served as a chimney, compressing the fire-laden air into funnels of flame.

The chain reaction of wildfire had begun. Heated plant matter released hydrogen and carbon while drawing in oxygen, and the whole of it was on the run, a weather system of its own. Thus, three small blazes in grass met six bigger ones in the lower forest and then merged with a dozen others before joining twenty or thirty more, until the mass was bundled into a single wall of yellow and orange moving upward at fifty miles and hour into the crowded zone of Douglas fir, spruce, and larch, into groves of wizened hardwoods and withered cedars next to dried-up streams, moving faster than a horse could run. All at once, it burned at the scrub and limbs of the lower tier of the forest, it burned at thick midheight, it burned large boughs, which broke away in the storm, huge cones popping in fireballs, and it burned at the crowns, the highest tips of the trees exploding into the air, flying off to light the crowns of other tall trees. The densest part of the forest, between three and five thousand feet above sea level, was ready-to-burn fiber when the flames moved through it. In pops and cracks and snaps and gulps, in gasps and whistles, the fire metastasized--more clamorous with every fresh intake, charging ahead. Any leftover little fire that might have smoldered and smoked in a last gasp was given new life by the wind, yanked from the ground, pitched into the river of flame, into the current of the now unrecognizable Palouser.

Midway through the Clearwater, the wall of flame took over the forest, hundreds of feet high, at least thirty miles wide in some parts, and still gaining strength, still fanning out, consuming oxygen in heaves, and pickup up intensity as its core temperature rose. The fire was a classic convection engine now: heat rising, pulling the hottest elements upward, a gyro of spark and flame. After racing through the Clearwater and Nez Perce forests, leveling nearly all living things in the Kelly Creek region, the fire swept up trees at the highest elevations. At this altitude, along the spine of the Bitterroots, the wind moved without obstruction, and the fire itself threw brands ten miles or more ahead of the flame front. The storm found the Montana border and spit flames down into the heavily settled Bitterroot Valley. It found the Lolo forest and crossed over the pass along the summits, jumping ridgeline to ridgeline. At the peak of its power, it found the Coeur d'Alene forest, leading with a punch of wind that knocked down thousands of trees before the flames took out the rest of the woods. By now, the conscripted air was no longer a Palouser but a firestorm of hurricane-force winds, in excess of eighty miles an hour. What had been nearly three thousand small fires throughout a three-state region of the northern Rockies had grown to a single large burn.

The advance force of the firestorm, just ahead of the flame wall, was so strong it uprooted bark-armored trees that had held to a piece of ground for three centuries or more. Entire sections of the forest were mowed down as if they were blades of grass. . . . Funnels, columns, and whirlwinds formed within the storm, each breaking out in a separate dance of gas and flames. Explosions and the charge of the wind brought a sound that shook any leaf of limb not consumed by flame. . . .

As the storm approached a piece of untouched ground, it announced itself with a roar and a light on the horizon and finished with a sea of flames, suffocating the woods. If there was a river in the way, the fire leapt over water. If there was a lake in the way, it rode its own wind to the other side and alighted on fresh timber. If there was a town in the way, it engulfed it without blinking, exploding a barrel of kerosene or a tank of oil, taking tents and timber, taking shellacked houses and plank sidewalks and cedar-shake churches, all ready for the burn.