Young Men & Fire by Norman Maclean - Essay Example

Young Men & Fire Fire Dynamics 5th May 2006 Young Men & Fire Young Men & Fire by Norman Maclean tells the story of the 1949 Mann Gulch incident in which all but three of a 15-man Forest Service crew of Smokejumpers, the elite fire-fighters who parachute into remote forests to control wildfires, died. Two teenage jumpers successfully raced the fire to a ridge and found a route to safety. Crew leader Wagner Dodge knew he couldn't make the ridge and instead established a "safety zone" by creating a small burned area that deprived the larger fire of fuel and gave Dodge some space in which to retreat. Many years later, Norman Maclean tried to re-enact the race up the hill and piece together the events of the Mann Gulch fire. In Young Men and Fire, he recounted his visits to fire research centers, discussions with the fire's survivors, and exploration of the canyon itself. His poetically written investigation into the events of Mann Gulch sought lessons from the fire while presenting pieces of beautiful writing on every page. The book is extremely compelling and use of language is both touching and elegant. Young Men and Fire combines a captivating primer on fires and firefighting, a powerful, amazingly real reconstruction of a tragedy, grief and human character. It is a magnificent drama of writing that pays tribute to the dead and offers rescue to the living. Maclean's quest for the truth that becomes an exploration of his own mortality, is more inspiring even than his journey into the heart of the fire. His description of the conflagration frightens, but it is his efforts to turn the story of the 13 men into tragedy that makes this book a classic. The Mann Gulch fire occurred when a wildfire in the Helena National Forest, Montana, United States, spread out of control. The fire was first spotted by a forest ranger around noon on August 5, 1949. James O. Harrison, the recreation and fire prevention guard for Meriwether Canyon Campground had quit his former job as a smokejumper to find a less dangerous profession. On this day however, he fought the fire on his own for four hours before he met the crew of smokejumpers who had been dispatched from Missoula, Montana, in a C-47. Foreman Wagner Dodge led the team towards the Missouri River. The fire however, spread faster than anticipated and had already cut off the path to safety. The men had to turn around. When Dodge realized that they would not be able to outrun the fire, he started an escape fire and ordered everyone to lie down in the area he had burnt down. The other team members hesitated and hurried towards the ridge of Mann Gulch instead. It was a mistake. Only two of them managed to escape through a crevice and found a safe location, a rock slide with little vegetation to fuel the fire. Two other members survived with heavy injuries but died within a day. Unburnt patches beneath the bodies indicated that the rest of the team, including Jim Harrison, suffocated before the fire caught up with them. Later 450 men fought for five more days to get the fire, which had spread to 18 km (4500 acres), under control. Wagner Dodge survived unharmed and died five years later of Hodgkin's disease. Lessons learned from the Mann Gulch fire had a great impact on firefighter training and over the years the science behind fire rampage continued to develop further. Numerous factors shape fire growth. In the case of Mann Gulch certain aspects led to one of the most violent of fire hazards, a blowup. This is a sudden increase in fire intensity or rate of spread strong enough to prevent or upset fire control measures. Blow-ups are often accompanied by violent convection and may have other characteristics of a fire storm. Sometimes flare-ups can occur where there is a sudden acceleration of fire spread or intensification. Unlike a blow-up, a flare-up lasts a relatively short time and does not radically change fire control measures. The most violent fire hazard is a fire storm, a violent convection caused by a large continuous area of intense fire, often characterized by destructively violent surface indrafts, near and beyond the perimeter, and sometimes by tornado-like whirls. These travel at great speeds and the rate of spread is another aspect of fire dynamics where its measurement is an important predictor of the expanse of its coverage and the time and resources needed to bring it under control. The rate of spread is the relative activity of a fire in extending its horizontal dimensions. It is expressed as a rate of increase of the total perimeter of the fire, as rate of forward spread of the fire front, or as rate of increase in area. Usually it is expressed in acres per hour for a specific period in the fire's history. In the Mann Gulch incident all these factors could have contributed to the surprising rate at which the fire spread. But other issues in fire behavior also contributed to the overall effect such as the influences of fuel, weather and topography. The terrain of Mann Gulch consists of canyons and ridges which are commonly associated with a large number of fatal accidents during forest fires all over the world. Experimental studies at laboratory scale on special test rigs using a range of canyon configurations showed that in practically all cases the rate of spread of the fire front is non-constant. The fire has a dynamic behavior and its properties depend not only on the canyon geometry but also on the history of fire development. The convection induced by the fire is enhanced by terrain curvature and the fire accelerates causing the well-known blow-up that is associated with canyon fires. The rate of spread of the head fire increases continuously even in the absence of wind or any other special feature or change of boundary conditions. The study results showed the important feedback effect of the fire on the atmospheric flow and how this affects fire behavior in canyons. Results from a field experiment carried out in a canyon-shaped plot covered by tall shrubs were used to validate the laboratory scale experiments. It shows that accidents may occur even in the absence of special fuel or atmospheric conditions as they are intrinsically related to terrain configuration. But fires themselves can be unpredictable with various factors influencing their behavior. Fire meteorology is extremely complicated involving diffusion flame, gravity and the three methods of heat transfer namely conduction, convection and radiation. Heat conduction is the transmission of heat across solid, where at a microscopic level, vibrating atoms generate heat throughout the solid. Heat transfer is always directed from a higher to a lower temperature. Denser substances are usually better conductors. When combustible material starts burning, heat and moisture are released causing horizontal gradients of buoyancy. Tornadic strength vortices or fire whirls created, travel downwards and feed the fire. At the same time, fire vortices enhance the mixing of air with flame, leading to higher flame temperatures, increased combustion efficiency, and greater intensity. Winds at the scale of the fire can be strongly modified or solely produced by the fire, depending on the level of atmosphere-fire interaction. Convection is heat transfer by mass motion of a fluid such as water or air when the heated fluid or gases is forced to move away from the source of heat, carrying energy with it. Convection above a hot surface occurs because hot air expands, becomes less dense, and rises. Another way fires 'evolve' is through diffusion. Diffusion not only refers to diffusion of particles, but also to all transport phenomena occurring within thermodynamic systems under the influence of thermal fluctuations (i.e. under the influence of disorder; this excludes transport through hydrodynamic flow, which is a macroscopic, ordered phenomena). In combustion, a diffusion flame is a flame in which the oxidizer combines with the fuel by diffusion. As a result, the flame speed is limited by the rate of diffusion. Diffusion flames tend to burn slower and to produce more soot than premixed flames because there may not be sufficient oxidizer for the reaction to go to completion. Diffusion flames tend to have a less-localized flame front than premixed flames. Diffusion flame configuration involves the migration (diffusion) of fuel molecules from the fuel supply toward the surroundings, combined with the diffusion of oxygen molecules from the surroundings toward the fuel supply. The two diffusing reactant streams meet within a narrow flame sheet where chemical reactions produce combustion products. The corresponding chemical energy release or reaction causes the region near the flame sheet to reach high temperatures. When fuel and air are supplied continuously, a steady flame is achieved by diffusion of combustion products and heat away from the flame sheet. Except for soot-emitting flames, soot tends to be both produced and consumed (oxidized) just inside the flame sheet; therefore, the outer boundary of the yellow luminous region roughly corresponds to the location of the flame sheet. The common distribution of a flame under normal gravity conditions depends on convection, as soot tends to rise to the top of a general flame, such as in a candle in normal gravity conditions, making it yellow. In microgravity or zero gravity, such as an environment in outer space, convection no longer occurs, and the flame becomes spherical, with a tendency to become bluer and more efficient. Several possible explanations have been proposed for this difference, of which the most likely is that the cause might be because the temperature is evenly distributed enough that soot is not formed and complete combustion occurs. NASA's experiments in microgravity reveal that diffusion flames in microgravity allow more soot to be completely oxidised after they are produced than diffusion flames on Earth, because of a series of mechanisms that behave differently in microgravity when compared to normal gravity conditions. It is the very presence of gravity that allows convection and consequently the distribution of flames over a terrain such as Mann Gulch that gives rise to the raging fires. Smokejumpers in their early days, were cautious and focused on getting to small fires and extinguishing them as soon as possible. The crew on the Mann Gulch fire was practically lacking experience on big fires. This proved fatal for most. Wagner Dodge's method of creating an escape fire thereby depriving the main fire of 'fuel' seemed the only option in an apparently inescapable scenario. He escaped the firestorm and lived long enough to tell his tale. Since then lessons have been learnt. Whereas most tragedies of this nature become statistics relegated to obscure pockets in history, Norman Maclean's Young Men and Fire brings the story of those brave firefighters on Mann Gulch to the forefront of our consciousness evoking a sense of loss, as well as affecting a new found respect to one of the most fearsome forces of nature - fire. References Maclean, Norman (1993). Young Men & Fire. University Of Chicago Press; Reissue edition Read More