The fire burned about 1.2 million acres (490,000 ha) and is the deadliest wildfire in recorded history,[1] with the number of deaths estimated between 1,500[1] and 2,500.

In the words of Gess and Lutz, in a firestorm "superheated flames of at least 2,000 degrees Fahrenheit ... advance on winds of 110 miles per hour or stronger.

When a firestorm erupts in a forest, it is a blowup, nature's nuclear explosion ... "[10]: 101 By the time it was over, between 1.2 and 1.5 million acres of land had been burned.

Peter Pernin, in his eyewitness account, states that the prolonged drought at that time combined with the factor of human carelessness were omens of the horrible disaster.

He also notes how the fire seemed to jump across the Peshtigo River using the bridges and upward air drafts and burn both sides of the town.

[18] Other survivors reported that the firestorm generated a fire whirl (described as a tornado) that threw rail cars and houses into the air.

[22] Certain behaviors of the Chicago and Peshtigo fires were cited to support the idea of an extraterrestrial cause, such as blue flames (thought to be cometary gases burning) in the basements of houses.

[20] However, modern fire theory indicates that the blue color was most likely a product of burning carbon monoxide in the poorly ventilated basements.

According to Sister Adele, in October 1859, she had a vision of the Blessed Virgin Mary with a warning, saying "If they do not convert and do penance, my Son will be obliged to punish them.

Some of the very few things that survived the Peshtigo Fire were the convent, school, and chapel and five acres of land that had been consecrated to the Virgin Mary.

[3] The American and British militaries studied the fire during World War II to learn how to recreate firestorms during bombing campaigns against cities in Germany and Japan.

"[9] Rutkow (2012) writes that the event prompted almost no change to the practices of the lumber industry or the way settlers approached life in forests.

[34] The Peshtigo Fire is discussed in Season 1, Episode 8, of the television series The Gilded Age when downstairs character Jack is discovered putting flowers on the grave of his mother, who died in the tragedy.