“When a firestorm erupts in a forest, it is a blowup, nature’s nuclear explosion…”

~Denise Gess & William Lutz, Firestorm at Peshtigo


On October 8th, 1871…

The Great Chicago Fire consumed the growing metropolis, killing 300 people and razing over 3 square miles. The fire burned for 48 hours, finally starving from lack of fuel.

A firestorm known as the Great Peshtigo Fire tore through northeastern Wisconsin, consuming several towns, killing from 1500-2500 people and turning 1.2 million acres into ash. It remains the deadliest wildlife in US history.

Three massive fires—the Holland Fire, the Port Huron Fire, and the Manistee Fire—erupted in Michigan. Known collectively as the Great Michigan Fire, they destroyed 2.5 million acres of first-growth forest and killed at least 500 people, with some estimates in the thousands.

All of this on the same day in 1871. 

The cause of the three fires, occurring hundreds of miles apart but in the same pocket of the Midwest on the same day, has baffled historians and scientists for over a century. No origin has yet been discovered. Coincidences happen, but labeling these disastrous fires as mere coincidence seems both heartless and brainless.

Was Mrs. O’Leary’s Cow to Blame? 

Mrs. O’Leary’s cow is the oft-repeated cause of the Great Chicago Fire, but this myth is equal parts ridiculous and revealing. Anti-Irish sentiment plagued Chicago immigrants in the 1870s, and an impoverished Irish-Catholic like Catherine O’Leary would have made a tempting target for angry (and mostly Protestant) Chicagoans.

This fable turned to fact when the rumors reached a reporter, and The Chicago Tribune published the O’Leary cow story before Chicago stopped smoldering. Mrs. O’Leary and her family quickly became outcasts, even among their fellow Irish; it wasn’t until 1893 that the Tribune admitted the story had been entirely fabricated. The city of Chicago, however, took its time admitting the mistake, and didn’t formally clear Mrs. O’Leary until 1997. Despite this acquittal, the myth persists, even to this day.

The Deadliest Wildfire in US History

Initially, blame for the Peshtigo Fire in Wisconsin fell to crews clearing forest land for residential and commercial building. In the 19th Century, lumber was plentiful in Wisconsin, and rather than mill and sell cleared logs, construction crews just set it on fire. But an exceedingly dry summer and powerful, autumn gusts turned the controlled burn into a firestorm, a phenomena in which fires burn so fiercely they create a self-sustaining wind system.

The Peshtigo Fire roared with winds over 100 mph and temperatures exceeding 2,000 degrees Fahrenheit. The fire burned so fiercely that it jumped the Peshtigo River, trapping the fleeing citizens. When Wisconsin state officials arrived to assess the damage, they discovered 1,182 of Peshtigo’s 1,749 residents dead, and buried nameless hundreds in a mass grave: all those that could identify them were gone as well.

Nature’s Nuclear Explosion

Almost 5% of Michigan’s entire acreage burned on October 8th, the fires fed by parched undergrowth, deadfall, and towering clusters of Eastern white pines. The Great Michigan Fire is the collective name for several localized blazes in the state: the Holland Fire on the western edge, the Manistee Fire in the state’s center, and the Port Huron Fire on the eastern edge.

No cause for the Great Michigan Fire has ever been pinpointed, only that the region’s conditions provided fertile ground for tragedy. Because of its remote location, the Great Michigan Fire, which tore a swath of destruction through the middle of the state, seems most tragic of all.

The scattered and unregistered population of the lumber industry and makeshift towns made it impossible to estimate the number of deaths. Because of this, the Great Michigan Fire has largely been eclipsed in the memoirs of history by the Great Chicago Fire, although the death toll in Michigan is very likely orders of magnitude higher.


Cause from the Cosmos?

Biela’s Comet, a well-known periodic comet of the mid-1800s, often receives much of the blame, but serious astronomers and meteorologists have dismissed the idea as ridiculous. The comet itself hadn’t been seen by astronomers since 1852, after the comet had fractured into two smaller pieces.

Even if the comet had reached Earth’s atmosphere, no fragments would have been hot enough to ignite fires; a fragment large enough to maintain a high temperature would have been destroyed in a dramatic air burst long before touching the ground. And in the three hundred years since the advent of astronomy, no meteorite has ever burned a blade of grass, much less started multiple wildfires.

Arson seems the most likely culprit, but it’s important to remember the time period. Although a person could easily zip from Wisconsin to Chicago to Michigan in just a few hours today, the Midwest of the 1870s was very different. The toddling railroad system in the United States had only a handful of lines available, especially with water transportation (Lake Michigan) so near. From Chicago, reaching Peshtigo in northeast Wisconsin would have taken most or all of a day, and Michigan would have been another several days’ travel.

Could the arson theory expand to a conspiracy, with several people involved? It could, but if so, you’d have to find at least three people both willing to commit the mass murder of innocent men, women, and children, and then remain silent for the rest of their lives. Silence is not a common attribute for sociopaths, and neither is cooperation. Like the comet theory, arson is possible, but very, very unlikely.

1852 SKETCH OF COMET BIELA

Acknowledging the Inevitable

Although not a cause, the dry conditions of the Midwest in 1871 are well-documented, with the Tri-State area experiencing an extended drought for two months before the fires. A Chicago weather service measured just over five inches of rainfall for the city from July to October, when the average was typically nine to ten inches. Peshtigo’s conditions were even harsher, with the city receiving less than five inches of rainfall in the same period: 12 inches was the city’s average.

These conditions, coupled with the fire-prone trappings of the time period—all-wood homes, reliance on wood fires, poor fire safety strategies, and rudimentary firefighting practices—made such blazes not only likely but inevitable; most reputable historians see the Midwest Fires of 1871 as a day of nightmarish coincidence. That answer is deeply unsatisfying, even if it’s the only one that makes sense.

Want to Know More? 

The Great Midwest Fires of 1871 may seem forgotten today, but there is an abundance of historic images documenting the tragic event, far more than I could feature in this article. Those interested may enjoy the informative slideshow “In Pictures: The Great Midwest Fires of 1871“.