willemite

UPDATED - July 5, 2012 - see link at bottom

This book tells the tale of a devastating conflagration that wiped out the town of Hinckley in the year 1894. The relevance to today as much of our country goes up in smoke cannot be overstated.

There is much information here that was news to me, details about prairie fires. Much of the book is taken up with a novelistic recreation of the actions of a host of real people, some of whom survived the event, most of whom did not. I found that I was not all that engaged with the personal struggles, but was far more interested in the scientific details. Obviously there is considerable overlap as the science describes how human beings are forcefully discorporated by a horrendous natural force.

P 64
[referring to Fire in America by Steven Pyne] In Pyne’s terminology, a mass fire that remains stationary is a firestorm; one that moves is a conflagration. Regardless of this finer distinction, though, all mass fires have certain characteristics that set them apart from ordinary wildfires. They are typically born when two or more smaller fires—often a main fire and the spot fires that it has spawned around its periphery—suddenly merge into a single eruption of flame. The flaming fronts may tower as high as one hundred feet over the tops of the trees, or two hundred feet above the ground. They may advance as fast at 15 miles per hour on level ground—much faster on a slope—and release energy at rates as high at 30,000BTU’s per foot of fire line per second. They create huge convection columns that loom over the surrounding countryside, radiating heat downward and thus drying out the fuel in their paths.

At one point, toward the peak of the Sundance Fire’s intensity, observers saw the side of an entire mountain, the west slope of Apache ridge, erupt into flames in a single instant. The angle of the ridge had exposed the mountainside to an enormous amount of radiant heat from the convection column, quickly drying out the forest and raising its temperature the kindling point. The first ember that landed on the mountainside had then ignited the whole thing as if it were soaked in gasoline.

P 65
Mass fires also generate enormous winds, often of hurricane velocity. Sometimes these winds begin to rotate and become cyclonic, creating fire vortices—tornadoes of fire that may advance well ahead of the main flaming front. Because of the tremendous draft in their convection columns, mass fires typically pick up thousands of flaming of glowing firebrands—some as large as burning logs. They may carry these as much as 18,000 feet into the air before throwing them miles ahead of their fronts, spawning spot fires wherever the firebrands land in fuel. And because mass fires consume their fuel so rapidly, they often exhaust all the available oxygen in the air before they have finished burning off all the carbon and volatile gases that they have released from their fuels. As a result they produce vast clouds of black smoke, black because it’s carrying a heavy load of unburned carbon. As this superheated carbon rises, it eventually encounters enough oxygen to allow combustion to resume, and flames arc in sheets across the sky. To people on the ground it appears that the sky itself is on fire. Most spectacularly of all, glowing bubbles of the gases released by fire—bubbles that may be as big as a car or even a house—may float some distance ahead of the fire like gigantic balloons dancing in the sky before igniting suddenly over the heads of onlookers.

P 79
[regarding a group of people in a clearing]
…there was fire on all sides of them now, and the heat was withering, searing their faces amd forcing their eyes shut. With every minute that passed, the heat was becoming more unbearable. Instinctively, people got down on their hands and knees and pressed their mouths close to the ground, sucking in cooler air. People prayed and cried and wailed. They gagged and wretched on the smoke. Some simply sat in the grass, staring at the approaching flames as is they could see something through them.

Soon the flames dropped down from the trees and dances along the edges of the clearing all around them, rippling through the grass that had looked so cool and green. They made a sharp crackling sound in the grass. Billows of sweet-smelling white smoke drifted up toward the black sky. Moaning, people rose and pulled away from the advancing flames, crowding each other, jostling each other as they pulled back, packing themselves into the very center of the clearing.

But within moments, there was no more room to pull back and the flames were upon them, lapping at their feet, blistering their ankles and shins, racing up their clothing, slapping at their faces. One by one, the women’s long dresses erupted—large tangerine-orange blossoms of fire wavering in the smoky gloom. Everyone screamed, but the screams came out thin and unnaturally high-pitched. The withering heat had dessicated their vocal cords, pulling them taught like overstretched rubber bands. Grown men suddenly sounded like young girls. When the screams were over they had to breathe in, and when they did they inhaled flames and superheated air, sucking the flames into their very mouths. Then, clawing at the air, black silhouettes dancing among the orange flames, they began to die.

P 83
Fire kills in several ways, depending on the circumstances. Some are much worse than others. The luckiest of fire’s victims die in their sleep, something that is surprisingly easy to do. All fires consume large amounts of oxygen and emit large amounts of carbon monoxide. They may emit a number of other gases as well, depending on the fuel that feeds them, and many of these gases, like carbon dioxide and cyanide, can also kill. But carbon monoxide kills the overwhelming majority of fire victims. Because it is tasteless and odorless, sleeping victims often never awaken to see, hear or smell the fire that kills them. The brain will scream out for more oxygen if carbon dioxide builds up in the lungs, but carbon monoxide is subtler. A stealth killer it sets off no alarms. It silently fills the lungs then—bonding to the hemoglobin in the blood 250 times more readily than oxygen to form a compound called carboxyhemoglobin (COHb)—it rapidly displaces the oxygen in the bloodstream. The brain and other vital organs are caught unawares. Suddenly deprived of oxygen, and having no other choice, vital organs such as the brain simply shut down, rather promptly. By the time the saturation of CODb in the bloodstream reaches 90 percent, death comes in minutes

Unfortunately, death by fire is not always so easy. Fully conscious victims, if they are surrounded by both flames and adequate oxygen, may remain alert until the flames have reached them and begun to consume their flesh. Oxygen ordinarily represents 21 percent of the air we breath, but we can generally maintain consciousness until the level falls to about 9 percent. Even if the flames themselves do not make it to conscious victims, it sometimes happens that those victims are forced to breathe superheated air—air that still contains some oxygen but is so hot that it burns away the soft tissues in their mouths, throats and vocal chords. These people know, for at least a few moments, what it is like to be burned alive, both from without and from within. If victims do not lose consciousness and there fore stay in one place anc continue to breathe the hot gases for a prolonged period of time, the damage from these hot gases may extend into their lower respiratory systems. Then even their alveoli, the 300 million or so tiny air sacks that line the lungs and transfer oxygen to the bloodstream, may be burned away, a fate that many people in the dry marsh north of the Grindstone probably suffered. But the fire has even worse to offer.

Fire always emits heat in the form of radiation. Radiant heat travels away from its source at the speed of light, so, for all practical purposes, it is felt instantaneously by anyone in the vicinity of a fire. This is the hat you feel on your face sitting in front of a fireplace on a cold winter’s evening. If you raise a hand, or any other shield, between your face and the fire, the heat on your face disappears immediately. The radiation emitted by a fire falls away fairly quickly with distance., so if you move your chair across the room it is likely that you won’t feel any noticeable heat on your face, though the air in the room may well be heated by convection from the fire. If the fire is big enough—say, a bonfire on a beach—you may have to stand quite a distance from it in order to be comfortable. But if it’s as big as a forest fire, you may not be able to get far enough away from it fast enough to avoid being broiled alive. This is the unkindest way fire kills, by the sheer application of heat. It is only likely to happen when the victim has enough oxygen to breathe for a sustained period of time—thus remaining fully conscious—but is still near enough to an overwhelming source of heat to be killed by it. Fortunately, since large fires consume enormous amounts of oxygen, this is relatively rare.


July 5, 2012 - Timothy Egan's column addresses what can only be called The Burning Time as the summer of 2012 puts the lie to deniers of global warming