The Hayman Fire: Extenuating Circumstances behind Colorado’s Largest Wildfire

CHE 2750
Spring 2005

A wildfire is a homeowner’s worst nightmare, and an out of control wildfire is a firefighter’s worst nightmare. Wildfires – fires that occur in open land and consume vegetation such as grass, shrubs, and trees as their fuel (Dehaan, 2002) – can occur anywhere and anytime. They may occur naturally, such as a fire ignited by lightning, or they may be the direct result of human activities, such as a careless camper or an arsonist. In 2002, the United States experienced its second worst fire season in the past half century (Reese, 2003), which included 88,458 fires that burned 6,937,584 acres (Wildland, 2005). According to an article from the National Fire Protection Association Journal, “ Colorado, Arizona, and Oregon all recorded their largest fires in a century” (Reese, 2003). In particular, the state of Colorado endured extraordinarily high numbers of wildfires. During June 2002, the Colorado experienced the largest wildfire in the history of the state: the Hayman Fire. Originating eight miles northwest of Lake George (Brobst, 2005), the fire spread quickly through the Pike-San Isabel National Forst and took weeks to battle; it eventually consumed 137,760 acres of forested land and destroyed 133 homes (Summary, 2003). The Hayman Fire response utilized thousands of personnel and millions of dollars in fire suppression activities, and still took weeks to contain because of its great size and extreme conditions. The combination of such factors as national drought, local fuel type, burn area topography, and human involvement resulted in a devastating forest fire.

According to Merrill Kaufmann of the U.S. Forest Service Rocky Mountain Research Station, “the ponderosa pine zone covers about 4 million acres along the Colorado Front Range” (2002). A forest is a remarkable ecosystem. Pine forests in particular, like that of the Pike-San Isabel National Forest, thrive in a diverse environment. They coexist with numerous plant and animal species in a tightly woven web. As a result of the sheer variety and interconnection between species, forests are very stable ecosystems. They are adaptable and can weather the occasional loss of a species or introduction of a new species. They can even survive fire. Historically, pine forests in moderate, non-drought environments have experienced cyclical cool surface fires that cleared ground material but left older trees untouched (Fire and Fuels, 2003). These small, natural fires burned away grasses, shrubs, and low branches, but many such plant species regenerate quickly after a fire. Most importantly, the ideal surface fire, based on historical examples of naturally occurring wildfires, consumes ground-level fuel and does not harm mature trees. Mature trees are often naturally protected from small to moderate fires by a thick layer of outer bark. An ideal surface fire does not develop into total forest involvement. The Hayman Fire began as a surface fire that quickly spread to a crowning fire, aided in part by drought conditions and fuel abundance.

Beginning several years before the Hayman Fire, the United States witnessed continually decreasing precipitation and humidity. By 2002, the Western U.S. was in a full blown drought. By March 1, 2002, the mountain snow pack in Colorado was well below normal, at only 56 percent (Vaughan et al, 2002). The U.S. Forest Service examined fuels along the Front Range and found their moisture levels to be less than 5 percent (Rocky Mountain Research, 2003), a percentage severely below normal. Fuel moisture content is important to the behavior of a fire. Fuels with high moisture content require the application of more heat energy to reach their auto-ignition temperature – the temperature above which they will combust. Thus, it takes longer for a moisture-rich fuel to burn, because it must be dried first by prolonged heat exposure. On the other hand, a very dry fuel, such as that found in the Pike-San Isabel National Forest, requires much less exposure to heat energy before combustion occurs. On June 8, 2002, when U.S. Forest Service employee Terry Barton started a campfire, a few errant sparks were apparently all the tinder-dry grass and shrubs needed to erupt in flame. It was a very dry day (Rocky Mountain Research, 2003), and the initial spread may have been caused by radiation to nearby fuels from the campfire and from the initial grass fire.

In addition to low humidity, Colorado weather also demonstrated high temperatures and high winds. During two time periods, from June 8-10 and June 17-18, all three weather factors combined to create especially extreme conditions on those days, conditions that optimized the rapid spread of the Hayman Fire (Summary, 2003). Twenty-four hours after ignition, the fire had covered 30,000 acres and was heading northeast to the Cheesman Reservoir. (Figure 1) Firefighters focused on containment of the fire, meaning their efforts were geared towards keeping the flames within a specific boundary (Brobst, 2002). Meanwhile, evacuations occurred in threatened communities; during the course of the fire, 51 mountain communities were evacuated (Reese, 2003). Quite clearly, weather plays an important role in the spread of wildfire. The abatement or reversal of just one weather factor on June 8, 2002, at the time of ignition and initial spread, may have drastically reduced the size and speed of the fire. Fortunately, weather conditions did ease somewhat between the two high activity periods (Rocky Mountain Research, 2003), allowing time for firefighters to organize evacuations and implement fuel treatment options.

Another important consideration in the spread and intensity of the Hayman Fire is the type of fuel present in the Pike-San Isabel National Forest. (Figure 2) While predominantly ponderosa pine, the forest also contains a large portion of Douglas fir, both of which have a high resin content that can increase rate of burn. Pre-fire, the forest contained a lot of surface fuel: grasses, shrubs, dead branches, young trees, etc. These materials were the product of more than a hundred years’ worth of accumulation, a result of increased human fire suppression activities over the past century. As humans have continually spread outward into their natural surroundings, building homes and communities, there has subsequently arisen the need to protect those communities and from the threat of fire. Over time, forest fires are contained and/or extinguished as soon as possible, to prevent any possible damage to nearby human settlers. The lack of natural fires has resulted in packed forests, filled now with surface fuel as well as younger, more fire-sensitive trees that have been allowed to grow.

As continual fire suppression occurs in a region, certain consequences must be acknowledged. First, the natural clearing of ground litter is a healthy occurrence in forests; fires release nutrients into the soil for future growth, and they increase biodiversity by removing a few shade trees to allow growth of sun-loving plant species. Second, the build up of ground litter is the build up of fuel. Surface fuel is light and small – pine needles, leaves, sticks, saplings – and burns quickly. As a result, a surface fire may have the potential to produce a larger fire. It is the forest’s natural mechanisms that prevent that from happening; regular fires keep the forest from becoming too dense and removes young, fire-sensitive trees from the area. Both of these actions aid in the reduction of surface-to-crown fire occurrences. Third, large amounts of surface fuel available during a forest fire will almost certainly lead to the development of a crown fire: a fire that reaches the top canopy of a tree and can spread quickly from treetop to treetop, consuming all it reaches. According to the U.S Forest Service, low branches of Douglas fir and ponderosa pine that normally wouldn’t have grown in the presence of regular fires “facilitated the transition of the fire from the surface to burning tree crowns” (Rocky Mountain Research, 2003), thus allowing the rapid spread of the Hayman Fire.

Another significant factor in the development, spread, and termination of the Hayman Fire is the topographical nature of the burn area. (Figure 3) Dense, continuous fuel sources – pine and fir trees – assisted the spread of the fire. Mountains to the west of the Hayman burn area and U.S. Highway 67 to the east formed the lateral boundaries of the fire (Finney et al, 2003). In the central and north central regions of the burn area, the South Platte River runs at a northeastern angle until it reaches the Cheesman Reservoir. During suppression of the Hayman Fire, the reservoir was a fortunate interruption in northern spread of the flames. Upon encountering the reservoir, the fire flowed around both sides of it, forming two distinct prongs. The eastern prong of the fire was stopped when it reached the recently burned area of the May 2002 Schoonover Fire (Rocky Mountain Research, 2003). The halt in progression saved the town of Decker from being evacuated. Furthermore, the fire slowed when it encountered several prescribed burn areas. The prescribed fires, such as the 2001 Pohemus prescribed fire, had removed surface fuels from the specified areas areas, and this in turn drastically reduced the spread of the Hayman fire in those areas. In a seemingly losing battle between fire and firefighters, this development blocked the Hayman Fire’s destructive path.

All a wildfire technically needs is fuel, oxygen, and an ignition source. The Hayman Fire had plenty of fuel and oxygen, and in a period of severe weather and environmental conditions, all that the available fuel required for ignition was a few small embers from a campfire. With such a drastic reduction in fuel moisture, forest material was ready to burst into flames no matter what the source of ignition. High winds were ready and waiting to spread any flames with which they came into contact, feeding them from the rear and pushing them forward onto new fuel. Dense fuel concentrations within the forest quickly resulted in the progression – from surface fuel, to intermediate branches, to treetops – of a crown fire. Once the crown fire was established, the fire was able to spread even more rapidly from canopy to canopy. Aided by the wind, the crown fire burned hotter and faster, and was able to cross roads and fuel treatment areas with little delay. Luckily, continued firefighter activities plus the encounter with several natural and man-made burn areas slowed the fire until the severe weather passed. As the largest fire in Colorado history, the Hayman Fire will not be forgotten. Rehabilitation efforts still continue to protect soil, water, and natural habitat (Brobst, 2005). There is one comforting fact; the forest will recover. Due to the extent and severity of the fire, the process may take longer than normal, but nature has its own mechanisms for dealing with disaster. Already, remarkably, three years after the fire, new life is growing in the Hayman burn area.

References

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DeHaan, J. (2002). Kirk’s Fire Investigation, 5 th Ed . Upper Saddle River : Prentice Hall.

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Rocky Mountain Research Station. (2003). Hayman fire case study analysis: Executive summary. USDA Forest Service [Online] Date Retrieved: 18 April, 2005. Available: http://www.fs.fed.us/rm/hayman_fire/text/01exe_summ/01exe_summ.html

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Vaughan, K., Hartman, T. & Sanchez, R. The Hayman war, the story of Colorado’s worst wildfire. (2005). The Rocky Mountain News [Online] Date Retrieved: 16 April, 2005. Available: http://denver.rockymountainnews.com/hayman/index.shtml

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