Patterns of fire occurrence in the Northern Rockies can be gleaned from written and oral accounts of past events. Newspaper articles, journal entries, and government documents, for example, have chronicled numerous forest fires in the region. Some of the earliest reports were penned by explorers in the mid 1800s.
From these sources we learn, for example, that smoke-filled summertime skies have long been a fact of life in this region. A National Academy of Sciences (NAS) report written at the turn of the 20th century bemoaned that "nearly every summer smoke obscures for months the sight of the sun over hundreds of square miles, and last summer [the NAS] committee, traveling for six weeks through northern Montana, Idaho, and Washington, and through western Washington and Oregon, were almost constantly enveloped in the smoke of forest fires" (Pyne 2001).
We learn that 19th-century forests were rife with evidence of past fires. For example, an early Anglo-European explorer noted "the charred remains of the previous forest found abundantly throughout the lodgepole-pine growth" and "defects . . . due to repeated fires" on the trunks of up to half of the ponderosa pines in stands within the Bitterroot Valley, Montana, circa 1898 (Leiberg 1898). From John Leiberg's 1898 account, 80% of the standing timber in lodgepole pine-dominated forests of the Bitterroot Valley had been severely burned within the previous 40 years. And he estimated 50% of Douglas-fir forests, 4% of mixed ponderosa pine and Douglas-fir forests, and 1% of pure ponderosa pine forests were severely burned during this same time-period.
We learn of fires in the 1800s that rival any present-day burns in terms of their size and severity. According to a government report, nearly 31% of the land now included within the Bob Marshall and Scapegoat Wilderness Areas of Montana burned sometime between 1859 and 1898 (Ayers 1901). One of the fires was an 800,000 acre stand-replacement event that occurred in 1889 (Ayers 1901).
We learn that not all fire years are created equal. Certain years have brought far more fire than others. Elers Koch, an early supervisor of the Lolo, Bitterroot, and Missoula National Forests, recalls 1910, 1914, 1917, 1919, 1925, 1926, 1929, 1931, and 1934 as the exceptional fire years of his career (Koch 1998).
One particular year in the region's recorded history is infamous for its forest fires. The spectacular fire season of 1910 crescendoed on August 20-21 near Couer d'Alene, Idaho, as several fires merged into a tremendous firestorm. This conflagration, known as the Big Blowup, burned more than two million acres in just two days and clouded skies from Montreal to Massachusetts (Pyne 2001). Pages upon pages have been written about the fires of 1910 and the Big Blowup. Some of the more dramatic - and gruesome - eyewitness accounts are posted on the Idaho Forest Products Commission website. These and other horrific accounts of the "Great Fires" shocked the U.S. government into a all-out war on forest fires - a war that has been only recently stepped down (Pyne 1982, 2001).
Ayers, H. B. 1901. Lewis and Clark Forest Reserve, Montana. USDI Geological Survey, 21st Annual Report, Part 5:27-80.
Koch, E. 1998. Forty Years a Forester: 1903-1943. Mountain Press, Missoula, Montana, USA.
Leiberg, J. B. 1898. Bitterroot forest reserve. USDI, Geological Survey, 19th Annual Report, Part 5:253-282.
Pyne, S. J. 1982. Fire in America: a cultural history of wildland and rural fire. Princeton University Press, Princeton, New Jersey, USA.
Pyne, S. J. 2001. Year of the fires: the story of the great fires of 1910. Viking Penguin, New York, New York, USA.