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Unit 9: Extreme Fire Behavior

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Examples of Fatality Fires

Now we want to illustrate further how some of the fatalities occurred. We have selected seven tragedy fires from which to discuss the circumstances involving the fatalities. On each of these, from 2 to 13 persons lost their lives.

Example 1

The first is the Mann Gulch Fire, which took place in the Helena National Forest, Montana in 1949. Here 13 men, mostly U.S. Forest Service smoke-jumpers, were overcome by a running surface fire in open timber.

The Mann Gulch Fire started on August 5. There had been an extended period without rainfall, thus making forest fuels very dry. A planeload of smoke--jumpers arrived over the fire that afternoon, sized it -up, and jumped nearby. While hiking down the ridge to the small timber fire in the base of Mann Gulch, they reported that they could easily handle the situation. Sometime after 1700 hours that day a thunderstorm cell passed through the area, and strong, gusty winds from the cell spread fire up the ridge and over the other side. Only a portion of the men were able to reach safety.

Example 2

The graphic above illustrates the Inaja Fire disaster. This occurred in the Cleveland National Forest in California in 1956. Here, 11 men were lost in San Diego Canyon when fire suddenly made an uphill run and overran them.

During that day, a flow of air from a Santa Ana across the top of a large canyon had created a stable air situation that served to hold down fire combustion. Warm temperatures and heating by the fire preheated and dried the light fuels. Volatile substances in brush probably produced gases which accumulated in less ventilated areas of the canyon. Crews in the canyon were attempting to secure firelines but were having difficulties with rolling firebrands on the steep slopes. About midafternoon, firebrands rolled into a draw above which firefighters were working. Shortly after, the Santa Ana lifted temporarily, removing the stable air "lid" from the canyon. Fire in the canyon quickly came alive and made an uphill run through the draw. Although fuels were somewhat sparse, the steep, rocky slopes made escape difficult for the firefighters working above.

Example 3

The figure above illustrates the Decker Fire disaster that took place in August, 1959 near the town of Elsinore, California. Here a total of six men died of burns when fire whirls came upslope and crossed the highway that was being used as a burnout and control line on the upper edge of the fire.

The fire was located on a 3,000-foot high, east facing front, above a large dry lake bed, called Lake Elsinore. Afternoon winds on the fire were-downslope, which is unique to this area. During the heat of the day, the large lake bed acted as a giant heat pump with heated air rising above the lake and air being drawn in from surrounding areas. At sundown, the heat pump stopped, and the downslope winds over the fire diminished. Heated air from the valley and very dry brush fuels provided the energy to generate the fire whirls.

Example 4

In the illustration above, we have the Loop Fire disaster. This occurred in November, 1966, on the Angeles National Forest, when a Forest Service inter-regional fire crew was caught in the path of a sudden up canyon run in a chimney canyon situation. The crew had been ordered to complete 200 feet of fireline through the head of a steep- box canyon to tie off and gain control of the 2,000-acre Loop Fire. They were working the fire's edge, cold trailing, which is considered the safest method in California brush fields. Santa Ana wind conditions had been prevalent for several days and caused the fire to spread mostly downslope throughout that day. At approximately 1535, the Santa Ana slackened, and fire burning in the base of the chimney began its death run. Ten fire crew members were immediately trapped and overcome by fire, while 12 others escaped with critical to minor injuries. Two of these died later.

Example 5

During the summer of 1967, the Sundance Fire in Northern Idaho stood out as a giant among several major fires in the Northwest that year. It made its major run within a 9-hour period, during which it traveled 16 miles, mostly by spotting, which occurred up to 12 miles ahead of the fire front. It engulfed more than 50,000 acres of timberlands and burned two men to death.

On August 23, that year, a weak cold front triggered dry lightning storms which started five fires in the vicinity of Sundance Mountain. Following this, a stable high-pressure zone settled over the area causing large-scale subsidence. As a result, a period of hot, dry weather followed. The last of the fires to be mopped up jumped firelines and began its major run at approximately 1400 on September 1. By 2300 that day, it had traveled 16 miles to the northeast.

Intermittent areas of timber and logging slash several years old were responsible for heavy volumes of available fuels. Strong winds that pushed the 4-mile wide front were caused by a rapidly approaching cold front. The Forest Service employee and dozer operator who died of burns were working in an area far ahead of the fire front and considered to be safe. However, long-range spotting in advance of the fire front quickly put them in the direct path of this conflagration.

Example 6

This figure illustrates the 1979 Romero Fire in the Los Padres National Forest which claimed four victims. Extreme fire whirls were observed that evening as a cat operator, spotter, and two firemen attempted to retreat through heavy brush on the slopes below the fire. The Santa Ana was again a factor. Extended periods of hot dry Santa Ana winds dried the already cured light fuels in brush fields.

During the day of October 10, a coastal sea breeze had been meeting and lifting the Santa Anas. Shortly after dark the Santa Ana overpowered the sea breeze and caused the fire to run downhill. Fire whirls developed from the intense heat generated in the heavy fuels, and escape was cut off for the four firefighters.

Example 7

One of the more recent disaster fires was the Bureau of Land Management Battlement Creek Fire in Colorado in July, 1976. Here, three firefighters were killed and a fourth severely burned when their primary escape route was cut off by a fire run from below.

The incident occurred during a burnout operation to secure firelines near the top of a ridge above the fire in a steep drainage. Normal fair weather patterns existed over the area. However, fuels and topography played a critical role in this incident. A late, hard, spring frost was responsible for a heavy kill of Gambels oak leaves and small branches in the fire area. Relatively warm, dry weather following the frost provided tall stands of dead, dry, light and brushy fuels. A southwest exposure with slopes up to 75 percent in the chutes below the ridge line was a significant factor.

Shortly after noon on July 17, burnout crews from below fired out fuels in the lower portion of the drainage with the intention of eliminating fuels inside the control lines. The burnout fire from below moved with moderate rates of spread upslope until it reached the steep chutes. At approximately 1430, this fire exhibited extreme rates of spread and cut off escape for firefighters above. Investigations later indicated that it was as much a communication problem as it was a fire behavior problem.

Copyright 2008, by the Contributing Authors. Cite/attribute Resource . admin. (2005, November 10). Unit 9: Extreme Fire Behavior. Retrieved January 07, 2011, from Free Online Course Materials — USU OpenCourseWare Web site: http://ocw.usu.edu/Forest__Range__and_Wildlife_Sciences/Wildland_Fire_Management_and_Planning/Unit_9__Extreme_Fire_Behavior_3.html. This work is licensed under a Creative Commons License Creative Commons License