Tornado disaster - Illinois, 1990

Morbidity and Mortality Weekly Report, Jan 18, 1991

Tornado Disaster - illinois, 1990

On August 28, 1990, from 3:15 to 3:45 p.m., the strongest tornado in northern Illinois in [is greater than] 20 years struck the towns of Plainfield, Crest Hill, and Joliet in Will County. As a result of the storm's impact phase, 302 persons were injured (28 fatally). This report summarizes an investigation of injuries and deaths that resulted from the tornado's impact.

The tornado's path was up to 1/2-mile wide and 16.5 miles long; wind speeds were [is greater than] 260 mph. National Weather Service criteria for issuing a tornado warning were not satisfied until the tornado had already touched the ground. Electrical power service to 65,000 customers and phone service to 10,000 residences were severed; in addition, the tornado destroyed three schools, a church, many businesses, 106 apartment units, and 470 single-family dwellings. The estimated cost of damages was $200 million (Will County Emergency Services Disaster Agency, unpublished data, 1990). Because no warning was provided, few persons sought a tornado shelter.

The investigation included a review of 350 emergency-room and inpatient medical records from eight hospitals to identify injuries sustained during the impact phase and the postimpact phase of the tornado. Ninety percent of affected persons were white and lived in predominantly residential subdivisions in three communities (1 ). Because many persons who were rendered homeless by the tornado relocated with relatives living in the area, more than 84% of the victims who sought medical care at hospitals could be contacted for telephone interviews.

An impact-related injury or death was defined as an injury or death caused by the direct mechanical effects of the tornado. Postimpact injuries were defined as injuries that would not have occurred in the absence of the tornado and that occurred within a 48-hour period following the tornado (e.g., from walking through the debris or cleaning up debris).

While most impact-related deaths occurred instantaneously, four persons with impact-related injuries died 2-8 weeks after the tornado. Of these four, one man died 8 weeks later from complications of chest trauma suffered during the impact phase.

Most (221 [63%) of 350) victims were treated initially at one of the eight hospitals; several of the more severely injured were transferred to tertiary-care facilities in other areas. Because the disaster occurred simultaneously with the change of work shifts for the nursing staff, approximately twice as many persons were available as would be expected in an average staffing pattern for that hospital; many physicians and off-duty nurses also volunteered services.

Of the 28 persons who died from impact-related injuries, eight were [is not greater than] 20 years of age (range: 1 month-69 years; mean: 34 years); 14 were male (Table 1). Seven persons died in one large apartment complex; eight, in vehicles; five, in schools; four, in houses; and two, outside. Three persons died at one high school, where -10 students crouched against the only hallway wall that did not collapse and, therefore, may have been protected from fatal or severe injury. Reported by: Staffs of the following hospitals: St. Joseph Medical Center, Silver Cross Hospital, Joliet, Loyola Univ Medical Center, Maywood; Christ Hospital and Medical Center, Oak Lawn; Copley Memorial Hospital, Aurora; Edward Hospital, Naperville; Palos Community Hospital, Palos Heights; Morris Hospital, Morris. R Empereur, G Wold, Will County Health Dept; D Krieger, J Sapala, MD, Will County Coroner's Office; Illinois Emergency Svcs Disaster Agency, ML England, MS, BJ Francis, MD, State Epidemiologist, Illinois Dept of Public Health. Disaster Health Svcs, American Red Cross, Washington, DC. Health Studies Br, Div of Environmental Hazards and Health Effects, Center for Environmental Health and Injury Control, CDC, Editorial Note: Tornadoes are one of the most lethal and violent of all natural atmospheric phenomena (2). Tornadoes usually appear as rotating, funnel-shaped clouds that extend toward the ground from the base of thunderclouds with whirling winds of high velocity. The wind clouds rotate around a hollow cavity in which centrifugal forces produce a partial vacuum (3). Severe tornadoes may be [is greater than] 0.6 miles wide, travel as far as 185 miles, and attain wind speeds of up to 310 mph. in the United States, the frequency of tornadoes varies by season: most occur from April through July during the late afternoon. Each year, almost 700 tornadoes occur in the United States; however, only about 3% result in casualties (3). Since 1950, tornado-related deaths have declined substantially because of improved warning systems and public response to warnings. Nevertheless, from 1953 through 1989, 3522 persons died as a result of tornadoes in the United States (4).

The tornado in Will County was atypical for several reasons. First, it was not characterized by a classic funnel appearance; instead, eyewitnesses described it as having a wall-like appearance. Second, it occurred in late August; 75% of tornadoes and almost all tornado-related fatalities occur by late July. Third, the Will County tornado approached from northwest to southeast; most tornadoes follow a southwest to northeast path (5). Fourth, it did not weaken or leave the ground for the entire 16.4 miles of its path. Finally, this tornado attained a rating of 5 on the Fujita scale-the maximum intensity for a tornado; based on this rating, the Will County tornado is among the highest 3% of the most violent tornadoes in U.S. history.