Canton, Illinois Tornado of 1975

The Canton, Illinois Tornadoes of 1975 is a destructive summer tornado event which occurred as part of a significant severe thunderstorm outbreak concentrated across northwest and west-central Illinois and eastern Iowa on the afternoon and evening of July 23, 1975.

First tornado

The first tornado of a complex combination of tornado family and extreme downbursts touched down at 4:30 p.m. about 14 miles (23 km) west of the small city of Canton and immediately grew to very large size in agrarian northwestern Fulton County, Illinois. It continued meandering through rural areas with an average movement of easterly roughly near Illinois Route 9 for 11.1 miles (18 km) before ending about one mile (1.6 km) southeast of Fiatt. Total damages were around $250,000.

Canton tornado

Before that tornado lifted, a second tornado had touched down at 4:45 p.m. on the east side of Fiatt and it too in conjunction with intense downburst winds proceeded in a meandering path roughly eastward roughly along Route 9. There was no break in the damage because of the proximity of the tornadoes and the accompanying exceptionally intense downburst activity.

This tornado roared into Canton with a damage path 1.5 miles (2.4 km) wide, essentially destroying or heavily damaging the entire southern half of the town. It devastated much of the downtown area, destroying or damaging 127 businesses. About 100 frame houses were destroyed and an additional 300 were damaged; 50 trailers were destroyed and another 100 were damaged. Two people were killed in trailers and 69 people were injured overall. Straight-line winds from downbursts inflicted less intense damage across the remainder of town. Total damages amounted to around $25 million (1975 USD). Some areas did not have power restored for a week. The National Guard was deployed, and the damage was so immense and overwhelming that the city was declared a federal disaster area. [ [http://www.fema.gov/news/event.fema?published=1&id=1679 FEMA: Illinois TORNADO ] ]

The high end F3 tornado continued for approximately another six miles (10 km) to about one mile (1.6 km) north of Banner for a total path length of 14 miles (23 km). Total tornado area was 37.5 sq. miles (60 km²) with a very high destruction potential index (DPI) -- integrating intensity, path length, and width [ [http://www.spc.noaa.gov/publications/thompson/dpi/dpi.htm Thompson's DPI paper (19th SLSC) ] ] -- value of 150.

Science benefits

It was first thought to be a single tornado event of over 25 miles (40 km), but a meticulous damage survey by the renowned severe weather expert Ted Fujita documented the complex interactions of downbursts, microbursts, and tornadoes, and much was learned meteorologically from this event. Downbursts covered a very large area; these as well as a continuous series of smaller but very intense microbursts were responsible for the meandering course of the tornadoes and for some changes in intensity. It is thought that a microburst may be responsible for breaking up the first tornado. A continuous damage swath connected the events regardless. Conversely, another microburst seems to have caused the tornado to intensify as it hit Canton, and this coincided with the two deaths. The most intense pure tornadic damage width was 0.5 miles (1 km).

1835 Canton tornado

Canton and surrounding areas were devastated by an earlier tornado on June 18, 1835. Touching down around 10 p.m., it decimated rural farms, killing four; before it traversed through Canton, killing four in town, including the town's founder and his young son. Injuries totaled forty. This tornado damaged or destroyed about fifty buildings in Canton with a total damage width of about one quarter of a mile (0.4 km).

See also

*List of North American tornadoes and tornado outbreaks

References

* Grazulis, Thomas P. (1993). "Significant Tornadoes 1680-1991, A Chronology and Analysis of Events". [http://www.tornadoproject.com/ The Tornado Project of Environmental Films] : St. Johnsbury, VT. ISBN 1-879362-03-1
* NOAA, "Storm Data"