Plainfield Tornado
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| Plainfield Tornado | |
| Date of tornado: | August 28, 1990 |
| Time: | 3:15 p.m. to 3:45 p.m. CDT |
| Rating of tornado: | F5 tornado |
| Damages: | $165 million |
| Fatalities: | 29 |
| Area affected: | Plainfield, Illinois, Crest Hill, Illinois, Joliet, Illinois |
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The Plainfield Tornado was a devastating tornado that occurred on the afternoon of August 28, 1990. It formed from a supercell thunderstorm which initially formed in the vicinity of Janesville in south central Wisconsin and produced a tornado near Pecatonia in Winnebago County, Illinois which touched down at 1:42 P.M. The storm moved southeast towards Oswego Kendall County. Continuing southeast, the tornado rapidly strengthened into a violent F5 tornado. At 3:30 P.M. CDT in Wheatland Township in Will County northwest of Plainfield the tornado damaged nearly all of the homes in Wheatland Plains subdivision where there were several injuries, but no fatalities. The storm caught drivers by surprise on US Highway Route 30 just south of 143rd Street where 3 drivers were killed. As the storm tore through the city, 9 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 storm. This was the deadliest tornado event in the region since the Belvidere - Oak Lawn Tornado Outbreak of April 1967.
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[edit] Tornado Table
| Confirmed Total |
Confirmed F0 |
Confirmed F1 |
Confirmed F2 |
Confirmed F3 |
Confirmed F4 |
Confirmed F5 |
| 9 | 4 | 3 | 1 | 0 | 0 | 1 |
[edit] Atmospheric conditions
For late August standards, August 28th was a very humid, very warm day. Temperatures reached into the low 90s Fahrenheit (about 11 degrees warmer than the normal of 79 degrees), but dewpoints soared into the upper 70s. The presence of such a high dewpoint 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 atmosphere. A warmer atmosphere inhibits the rising of surface air through the atmosphere — a requirement for precipitation, in the form of humid surface air condensing in a cold atmosphere, to occur. This is known as a "capped" atmosphere.
The atmosphere on the 28th was significantly more unstable, although the wind fields (strong, but out of the west-northwest) were not suitable for tornadic development. As a result of the high dewpoint, CAPE values (Convective Available Potential Energy) were in excess of 8,000 J/KG; generally, values of 1,500 are considered to be moderately unstable, whereas values of more than 5,000 are considered "Highly Explosive." The energy in the atmosphere required lift to initiate into thunderstorms; at this time, the LI (Lifted Index) was a number used to measure the overall amount of lift in the atmosphere. A LI value of -6 or below supports severe thunderstorm development, but during the day the LI value ranged from -12 to -14.
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 situation slightly more favorable for tornadic development. Once a tornado formed, the extreme instability contributed heavily to its rapid development into a one-half mile (.75 km) wide tornado.
[edit] Tornado touchdown, path, and damage
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In Kendall County, the supercell spawned a microburst near Oswego, strengthening to an F5. The tornado traveled southeast through Wheatland Township Will County, moving into Plainfield, Illinois around 3:28 P.M. By 3:30 P.M., the tornado had directly struck Plainfield High School, killing two people, including a science teacher preparing for classes the next day. The tornado demolished the Plainfield School District Administration building where a secretary was killed. The tornado crossed Route 59 (Division Street) and ripped into St. Mary Immaculate Church and school claiming an additional 3 lives. The storm 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. (An additional 3 people would later succumb from injuries sustained during the storm). The tornado then moved towards Crest Hill. At 3:38 P.M. the storm ripped through the Crest Hill Apartment complex where it caused more F5 damage and claimed another 8 lives. Two people died while in their car on Cedarwood Drive outside the apartment complex. In all a total of 29 people would die because of the Tornado.
It continued as a thunder storm until it crossed over the Indiana border where it petered out around 4:30 P.M. The Plainfield Tornado traveled a distance of 16 miles (26 km) in 8 minutes causing over 140 million dollars worth of damage.
[edit] Aftermath
[edit] 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 near west side of Joliet in 2004.
[edit] 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 would only show a severe storm, 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.
Partially in remembrance of the Plainfield tornado, the National Weather Service installed the next generation radar in nearby Romeoville. It replaced an older generation of radar further to the southwest in Marseilles.
[edit] Forecast criticism
In the months following the tornado, the National Weather Service was heavily criticized for providing no warning of the approaching tornado. 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.
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. In addition, the office was concerned about issuing warnings for situations that were not necessarily severe. At some point after the 1990 tornado, the National Weather Service reduced the Chicago office's workload by creating an office in Lincoln, Illinois and allowing offices in the Quad Cities, St. Louis, Missouri, Indianapolis, Indiana and Paducah, Kentucky to issue forecasts for their respective areas.
[edit] Illinois' Tornado Alley
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This section is a stub. You can help by expanding it. |
The Plainfield Tornado was the latest example in a continuing observation; that southwest suburbs of Chicago, and Will County in particular, are more prone to tornadic activity than areas to the north and east. Meteorologists have theorized that this is due to the stabilizing presence of Lake Michigan and the fact that Will County is closer to the main Tornado Alley than Chicago is, even if only by 40 miles (65 km). It is worth noting that there are examples of tornadoes happening closer to the city of Chicago itself. The best known example would be an F4 that heavily damaged portions of Oak Lawn in 1967 and portions of the south side of Chicago, that caused 33 deaths. Part of Will County, only in Illinois*, Will County is part of the Illinois Tornado Alley.[1]
[edit] See also
- List of tornadoes and tornado outbreaks
- Utica, Illinois Tornado Outbreak — a similarly unexpected tornado outbreak caused largely by small-scale changes in the surrounding meteorological environment.
Plainfield was hardest hit.
[edit] References
- ^ National Weather Service via ComPortOne
- 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.
[edit] External links
- Tornado Disaster -- Illinois, 1990 (CDC, MMWR 40(2); 33-36)
- Plainfield, IL Tornado 1990
- Plainfield Tornado History (Plainfield Public Library)
- Northern Illinois Storm Lab
- Reflections on the Plainfield tornado by Tom Skilling
