Yellowstone fires of 1988: causes, course, and aftermath

In the eastern United States, with its heavy rainfall, wildfires tended to be small and rarely posed a major threat to life and property. As white immigrant settlements moved farther into the drier areas of the West, they encountered their first large fires. Wildfires in the Great Plains and forest fires in the Rocky Mountains were significantly larger (wildfire) and more destructive than anything they had previously seen in the eastern part of the country. A series of catastrophic fire events massively influenced fire management rules over the years.

The wildfire that claimed the most lives in U.S. history was the Peshtigo Fire, which swept through Wisconsin in 1871, killing over 1,500 people. The Santiago Canyon Fire of 1889 in California and especially the Great Fire of 1910 in Idaho and Montana led to the philosophy that fires are a danger that must be suppressed. The "Great Fire" of 1910 devastated 12,000 square miles of land, destroyed a number of communities, and took the lives of 86 people. This event led many land management agencies to call for wildfire suppression. U.S. governorate land management agencies, including the National Park Service followed fire management rules established by the U.S. Forest Service, which oversees most U.S. forests.

Until the mid-20th century, most foresters believed that fires should be fought at all times. Beginning in 1939, National Park Service work regulations specified that all forest fires should be extinguished by 10 a.m. the morning after they were first discovered. Thus, firefighting teams were established throughout the country and usually staffed by young men during the fire season. Beginning in 1940, firefighters known as smokejumpers would parachute from airplanes to put out fires in remote areas. By the start of World War II, more than 8,000 towers had been erected in the United States for fire watch. Later, many of them were demolished as aircraft were increasingly used to locate forest fires; today, only three towers are in operation annually in the entire Yellowstone Park. Fire prevention efforts were very successful: while an average of 30,000,000 acres (120,000 km²) fell victim to flames annually in the 1930s, by the 1960s this area had been reduced to between 2,000,000 (8,100 km²) and 5,000,000 acres (20,000 km²). The demand for timber during World War II was high, and any fire that destroyed forested areas was considered unacceptable. In 1944, the U.S. Forest Service conducted a public education campaign that emphasized the harmfulness of all fires. This campaign used a cartoon of a black bear named "Smokey Bear." This iconic firefighter bear can still be seen today on signs with the slogan "Only you can prevent forest fires." Initial posters featuring "Smokey Bear" left the public under the misapprehension that the wildfires were primarily caused by humans. In Yellowstone, the percentage of human-caused annual fires ranges from 6 to 10 on average, while 35 fires are started by lightning. Some scientists, as well as some logging companies and private citizens, learned that fire is a natural component of many ecosystems: fire helps thin out the understory and dead wood, allowing economically important tree species to grow with less nutrient competition. Native Americans often burned forest areas to contain excessive growth, increasing the area of grassland for big game such as bison and elk.

As early as 1924, environmentalist Aldo Leopold wrote that natural fires are beneficial to the ecosystem and the natural reproduction of various tree and plant species. For the next 40 years, more and more foresters and ecologists agreed with the assessment that occasional fires were beneficial to the ecosystem. In 1963, ecologists recommended to the National Park Service in a report, the Leopold Report, that regular natural fires be allowed to restore the natural balance in the parks. The Wilderness Act of 1964 helped solidify the role of fires as a natural part of the ecosystem. The National Park Service adjusted its fire action directives in 1968 to reflect the changing view. The administration determined that natural fires started by lightning should be allowed to continue burning as long as they posed little danger to people or their property. The administration additionally determined that controlled fires could be deliberately set under prescribed conditions to restore ecological balance. The ecological purpose of fire became better understood after many forests aged and became overdue for large-scale fire.

Since 1972, the National Park Service has allowed natural fires in Yellowstone to continue burning under controlled conditions. Fires of this type are referred to as prescribed natural fires. Between 1972 and 1987, a total of 235 of these prescribed natural fires burned a relatively small area of 137 square miles. Only 15 of these fires reached a size of more than 0.4 km². The five years leading up to 1988 were significantly wetter than normal, resulting in smaller fire areas during this period. The policy of prescribed natural fires seemed, especially for the Yellowstone region, to be an effective way to deal with fires.