1990 Plainfield Tornado

The Plainfield tornado was a devastating tornado that happened on the afternoon of Tuesday, August 28, 1990.

The violent tornado killed 29 people and injured 350. It's the only F5 tornado ever recorded in August and the only F5 tornado to ever strike the Chicago area.

It formed from a supercell thunderstorm, which initially formed in the vicinity of Janesville in south central Wisconsin and produced a tornado near Pecatonica in Winnebago County, Illinois, which touched down at 1:42p.m. That tornado did not live long, but the storm continued to move southeast toward the Aurora area, but with no official touchdown and only minor roof damage. Continuing southeast, a tornado touched down and rapidly strengthened into a violent F5 tornado.

At 3:30p.m., the tornado damaged nearly all of the homes in a Wheatland Plains subdivision where there were several injuries, but no fatalities. The storm caught drivers by surprise on U.S. Route 30 just south of 143rd Street where three drivers were killed.

The tornado was incredibly hard to spot because it was "rain wrapped," which means rain is rapidly spinning around the funnel. This makes the tornado almost invisible.

As the storm tore through the city, nine people were killed (one additional victim would die afterwards from carbon monoxide poisoning while guarding his home after the storm). The remaining victims were from Joliet and Crest Hill in eastern Illinois. A total of 350 people were also injured in the storm. This was the deadliest tornado event in the region since the Belvidere-Oak Lawn tornado outbreak of April 1967.

Atmospheric Conditions
For late August standards, August 28th was a very humid, very warm day. Temperatures reached into the low 90s (about 11 degrees warmer than the average of 79 degrees). Dew points soared into the upper 70s. The atmosphere was very unstable with a low-pressure system approaching from the northwest. Conditions were ripe for severe thunderstorm development.

Aftermath
The Plainfield tornado challenged both meteorologists and citizens in terms of tornado preparedness. Substantial safety measures were enacted in the years following the tornado; among these are frequent and regular tornado drills performed in schools.