Great Lakes fires of October 1871: Chicago, Peshtigo, Holland and Manistee

Background. A dry summer in the Midwest created conditions for rapid fire expansion. On October 8, 1871, strong winds from a weather front generated blazes from available ignition sources. This led to simultaneous fires in Illinois, Michigan, and Wisconsin, including the Great Chicago Fire and the Peshtigo Fire, which occurred on the same day.

Impact. The Great Chicago Fire destroyed 17,000 structures and left more than 100,000 residents homeless. The Peshtigo Fire burned about 1.2 million acres and is the deadliest wildfire in recorded history, with deaths estimated between 1,500 and 2,500; it remains the deadliest in the history of the United States. Holland and other nearby areas burned to the ground, while the lumbering community of Manistee also went up in flames.

Causes. Speculation suggests a common root cause for the fires, possibly fragments from Biela's Comet, though the comet's orbit did not intersect Earth until 1872. A more accepted explanation is that a dry summer and strong winds from a weather front triggered the firestorms, creating a blowup in the forests.