the great peshtigo fire
On October 8, 1971 in Wisconsin, a forest fire broke out and burned an area 10 miles wide and 40 miles long. This fire killed over 1000 people, flattened two towns, and burned about 1.5 million acres of land. The fire's exact cause is not known, though it was caused by a mix of human and environmental factors. The year 1871 was unusually dry and hot. Settlers and lumbermen took advantage of the dry weather to cut down trees. Poor lumbering practices lead to large slash piles (sawdust and unused trees), which meant that there was more for the lumbermen to burn. On October 8th, these slash burns took a bad turn and unexpectedly turned into a forest fire. This fire quickly raged through the towns due to wind from a cyclonic storm that was circling the region. Because of this, it is often called a firestorm.
An illustration of people fleeing from the fire. Anywhere between 1000 and 2400 people were killed from this firestorm.
Picture Source: http://digicoll.library.wisc.edu/WIReader/WER2002-3.html