1990 Plainfield tornado

1990 Plainfield tornado
Date:	August 28, 1990
Time:	3:15 p.m. to 3:45 p.m. CDT
Rating:	F5 tornado
Damages:	$165 million
Casualties:	29
Area affected:	Plainfield, Illinois, Crest Hill, Illinois, Joliet, Illinois

The 1990 Plainfield tornado was a devastating tornado that occurred on the afternoon of Tuesday, August 28, 1990. The violent tornado killed 29 people and injured 353. It is the only F5 tornado ever recorded in August and the only F5 tornado to ever strike the Chicago area. There are few known videos or photographs of the tornado.

Atmospheric conditions

For late August standards, August 28 was a very humid, very warm day. Temperatures reached into the low 90s ºF (about 11 °F warmer than the normal of 79 °F), but dew points soared into the upper 70s °F. The presence of such a high dew point did not necessarily predict a severe thunderstorm outbreak; the prior day, similar conditions existed in northern Illinois with the exception of a warmer mid level troposphere. A warmer atmosphere inhibits the rising of surface air through the atmosphere; a requirement for convective precipitation, that is, precipitation resultant from humid surface air ascending to condense in a cooler atmosphere above, to occur. This warmer air aloft can describe either, or both, weak lapse rates thus weak instability or a capping inversion.

The atmosphere on the 28th was significantly more unstable as the approach of a low-pressure system from the northwest cooled the mid levels (and also caused dynamic lifting) as instability continued to build in the capped, muggy environment, although the wind fields (strong, but out of the west-northwest and unidirectional) were not suitable for significant tornadic development. As a result of the very high low-level temperature and dew point, convective available potential energy (CAPE) values were in excess of 8,000 J/kg; generally, values of 1,500 J/kg are considered to be moderately unstable, whereas values of more than 4,000 J/kg are considered "extreme". The lifted index (LI), the dominant estimate of instability used at the time, was also extreme. Generally, an LI value of -6 °C or below readily supports severe thunderstorm development, but during the day the LI value ranged from -12 °C to -14 °C. Such extreme instability can lead to explosive thunderstorm development, very strong updrafts, and modulates the updraft to better enable tornadogenesis.

Conditions were ripe for severe thunderstorm development, and with both low level and high level steering winds from the west-northwest, the National Severe Storms Forecast Center issued a Severe Thunderstorm Watch for northern Illinois valid 1:30 p.m. through 8:00 p.m. CDT that night. The NSSFC predicted a derecho-type event for later that night as rapidly developing thunderstorms along a cold front in Wisconsin would be carried by the steering flow into the Chicago area. One of these storms developed supercellular characteristics south of Rockford, steering 30 to 40 degrees to the right of prevailing steering winds. By now, mid-level steering winds had begun to veer, causing a wind profile slightly more favorable for tornadic development. This helped develop a high precipitation supercell.

The "HP" supercell produced multiple funnel sightings, hail damage, and damaging winds south of Rockford before heading southeast toward Will County and dropped a rain wrapped tornado. This is why many in the path did not see the actual tornado but more of a wall of water and dark clouds coming toward them. As the storm continued south it produced a 16-mile swath of damage ranging from F1 to F5. The National Weather Service in Rosemont, IL (serving all of Central and Northern Illinois at the time) did not issue a Tornado Warning until 10 minutes after the tornado had hit Plainfield. Using the traditional radar technology at the time (until the installation of NEXRAD Doppler Radar) the storm had a well defined "hook echo" meaning the radar was picking up the wrapping of the rain around the circulation of the tornado.

Event summary

The tornado 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 near Rockford which touched down at 1:42 p.m. That tornado did not live long, but the storm continued to move southeast towards the Aurora area, but with no official touchdown and only minor roof damage.

Continuing to move to the southeast, the supercell spawned a tornado that touched down near Oswego in Kendall County, eventually and rapidly strengthening into a violent F5 tornado. The tornado traveled southeast into Wheatland Township Will County, near the Wheatland Plains subdivision, northwest of Plainfield. At 3:30 p.m. CDT in Wheatland Township, the tornado damaged nearly all of the homes in a Wheatland Plains subdivision where there were several injuries, but no fatalities. 12 homes were destroyed in Wheatland Plains.

The tornado struck Plainfield, Illinois around 3:28 p.m. Around 3:30 p.m., the tornado directly struck the Plainfield High School, killing three people, including a science teacher and two maintenance workers. Students who had been out practicing for the fall football programs ran into the high school to take shelter a few minutes before the storm hit. After an alarm was pulled by a dean in the main office, the volleyball players preparing for a game in the gymnasium rushed to the nearest door and took shelter in the hallway. It is reported that as soon as the last player was through the door, a coach quickly closed it, only for it to be immediately ripped back off by the storm. The gymnasium proceeded to fall apart and crash down filling the gap in the doorway. They took shelter in the same hallway as the football team, and once the tornado had passed, that was the only hallway left standing in the building.

The tornado then demolished the Plainfield School District Administration building, where the wife of a custodian was killed. The tornado crossed Route 59 (Division Street) and ripped into St. Mary Immaculate Church and school, claiming an additional 3 lives, including the principal of the school, a music teacher, and the son of the cook at the rectory. 55 homes were destroyed in Plainfield itself, and a strip mall and grocery store east of the high school and north of St. Mary Immaculate were damaged. Gravestones in the nearby cemetery were toppled.

The storm caught drivers by surprise on U.S. Route 30 just south of 143rd Street, where three drivers were killed.

The storm then worked its way southeast through the large city of Joliet, damaging homes in the Crystal Lawns, Lily Cache and Warwick subdivisions killing 5 more people, one in Lily Cache subdivision of Plainfield, and two each in Crystal Lawns and Warwick subdivisions; an additional 3 people would later succumb from injuries sustained during the storm. The tornado ripped through the Grand Prairie Elementary School (Plainfield School District), causing significant damage. Observers watched from the doors at the Louis Joliet Mall, as the tornado passed just southwest of them. 69 homes were destroyed in Crystal Lawns, 75 homes were destroyed in Peerless Estates, 55 homes were destroyed in Lily Cache, and 50 homes were destroyed in Warwick. Most of the homes in Peerless Estates and Warwick were newly built.

The tornado then moved towards Crest Hill. At 3:38 p.m. the storm ripped through the Crest Hill Lakes Apartment complex, where it caused F3 damage and claimed another eight lives, destroying one apartment building and half of another apartment building. Neither have been rebuilt. The tornado also ripped through the Colony West subdivision, destroying 12 townhomes, none of which have been rebuilt. A married couple died while in their car on Cedarwood Drive outside the apartment complex. The tornado then destroyed three apartment buildings on Elizabeth Court. Three more homes were destroyed in Bridalwreath, southeast of Elizabeth Court.

Further southeast, the tornado lost strength until lifting near Woodlawn Avenue and Campbell Street in Joliet. The parent thunderstorm continued until it crossed over the Indiana border, where it dissipated around 4:30 p.m.

The Plainfield Tornado caused over $140 million dollars worth of damage. As the storm tore through Plainfield, nine people were killed (one additional victim would die afterward, from carbon monoxide poisoning, while guarding his home after the storm). The remaining victims were from Joliet and Crest Hill, in North Eastern Illinois. In all a total of 29 people would die because of the tornado. A total of 350 people were also injured in storm. This was the deadliest tornado event in the region since the Belvidere - Oak Lawn tornado outbreak of April 1967.

Tornado table

Confirmed Total	Confirmed F0	Confirmed F1	Confirmed F2	Confirmed F3	Confirmed F4	Confirmed F5
13	5	4	2	1	0	1

F#	Location	County	Time (UTC)	Path length	Damage
Illinois
F1	SE of Pecatonica	Winnebago	1842	3 miles (4.8 km)
F5	Oswego to Joliet	Kendall, Will	2030	16.4 miles (26.2 km)	29 deaths
Ontario
F2	Komoka area	Middlesex	2110	unknown
F3	Frome/Port Stanley area	Elgin	2130	unknown
F1	Newtonville area	Durham	2220	unknown
Michigan
F1	S of Petersburg	Monroe	2150	15 miles (24 km)
New York
F0	NW of Falconer	Chautauqua	2250	4 miles (6.4 km)
F0	W of Limestone/Allegany State Park	Cattaraugus	2315	0.5 miles (0.8 km)
F2	E of Hector	Schuyler	2320	2.5 miles (4 km)
F0	Syracuse area	Chautauqua	0001	6 miles (9.6 km)
F1	SW of Gulph	Herkimer	0020	2 miles (3.2 km)
F0	SE of Duane Lake	Albany	0130	0.3 miles (0.5 km)
Sources: Tornado History Project Storm Data - August 28, 1990, 1990 Ontario tornadoes

Aftermath

Tornado preparedness

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.

After the tornado, meteorologists studying tornadic patterns in the area found that a major tornado (F3 or higher) strikes Will County about every 12 to 15 years. There have been no major tornadoes in the county since 1993. However, an F1 tornado swept through the historic Cathedral Area in the near west side of Joliet on April 20, 2004 (April 2004 Utica tornado outbreak). There was another tornado (EF0) in Plainfield in April 2007 that caused damage to a nursing home and a few homes. The twister lasted for three miles and ended up in Bolingbrook.

Deployment of NEXRAD

The development of NEXRAD (Next Generation Radar) contributed greatly to the ability of meteorologists to recognize tornadic activity. Where previous generations of radar could show only reflectivity data and no direct information on air flows (although tornadic supercells and tornadic signatures such as the hook echo and bounded weak echo region (BWER) were identifiable), NEXRAD contained the ability to detect the wind speed and direction inside the storm. The ability to see rotation inside a storm on both the microscale (tornadic) and mesoscale (supercellular) measurements has allowed forecasters to issue severe thunderstorm and tornado warnings in more timely fashion and with a higher probability of detection.

Forecast criticism

In the months following the tornado, the National Weather Service was heavily criticized for providing no warning of the approaching tornado. The NOAA Disaster Survey Report was highly critical of the forecast process within the Chicago office as well as coordination with local spotter networks and the preparedness of these groups. Prior to 1990, the National Weather Service in Chicago was responsible for providing forecasts for the entire state of Illinois.

As the Chicago office was overwhelmed with its workload, no warnings were issued by the office until 2:32 p.m. — nearly an hour after the first tornado was sighted southeast of Rockford. A second severe thunderstorm warning was issued almost an hour later at 3:23 p.m., but this provided no indication that a tornado was on the ground and did not mention the area where the tornado had tracked. No tornado warning was issued until after the tornado lifted.

According to the Chicago Tribune, NWS Chicago had "the worst record in the nation" for issuing warnings for severe storms, only issuing warnings 24% of the time when a warning was justifiable. Even today, many meteorologists refer to the "Plainfield Syndrome" as the idea that it's better to issue too many warnings and be wrong than to miss one critical warning, as was the case for the Plainfield Tornado. At some point after the 1990 tornado, the National Weather Service reduced the Chicago office's workload by creating an office in Romeoville, Illinois and allowing offices in the Quad Cities, St. Louis, Missouri, Indianapolis, Indiana and Paducah, Kentucky to issue forecasts for their respective areas.

See also

• List of tornadoes and tornado outbreaks
  • List of North American tornadoes and tornado outbreaks
• List of tornado-related deaths at schools
• April 2004 Utica tornado outbreak — a similarly unexpected tornado outbreak caused largely by relatively minor changes in the surrounding meteorological environment.

References

• Baumgardt, Dan A. (1992). A Three-Dimensional, Subjective Investigation of the Synoptic and Mesoscale Environment for the Plainfield/Crest Hill, Illinois Tornado August 28, 1990. M.S. Thesis, University of Wisconsin–Madison.
• Brenner, Sue Anne, and Eric K Noji (1995). "Tornado Injuries Related to Housing in the Plainfield Tornado". International Journal of Epidemiology, vol 24, no 1, p 144-9.
• Fujita, T.T. (1991). "Plainfield tornado of 28 August 1990". WRL Research Paper 234, University of Chicago, 25 pp.
• NOAA (May 1991). "The Plainfield/Crest Hill Tornado", Natural Disaster Survey Report.
• Beaird, Tina (2005). "Black Sky: Plainfield Tornado August 28, 1990". Plainfield. Plainfield Public Library; Local History Collection. 142pp.

External links

• Map of August 28, 1990 Tornadoes Tornado History Project
• Tornado Disaster -- Illinois, 1990 (CDC, MMWR 40(2); 33-36)
• Plainfield, IL Tornado 1990
• Video Clips of the Aftermath
• Plainfield Tornado History (Plainfield Public Library)
• Plainfield Tornado - 20 Years Later (WGN)
• Reflections on the Plainfield tornado by Tom Skilling
• Federal Disaster Declaration (Federal Emergency Management Agency)