An August nightmare: the unwarned Plainfield tornado of 1990
By Jared Shelton News-Press NOW meteorologist
The last week of August can bring a variety of weather to the American Midwest. Heat, humidity and sunshine are common themes from year to year, along with occasional cooler and drier spells as well. Although late August is not typically a hotbed for tornadic thunderstorms for much of the heartland, the dog days of summer have produced impactful tornadic events, some that rival even the strongest springtime twisters.
This past Wednesday marked 34 years since the infamous F5 Plainfield, Illinois, tornado of 1990, the strongest tornado to ever strike the United States in the month of August to date. More surprisingly, the killer tornado was not warned by the National Weather Service throughout the duration of its 16.4-mile path, where it shredded neighborhoods in the western suburbs of Chicago, resulting in 29 deaths and over 300 injuries.
The Plainfield tornado tragedy was ultimately the result of a perfect storm of circumstances. On one end, a uniquely volatile and complex meteorological scenario. On the other, an overworked, ill-equipped National Weather Service Chicago office, lulled into complacency by the anomalous set of circumstances and lack of modern-day technological advances.
Not dissimilar from hot and humid late-summer days here in Northwest Missouri, the afternoon of Aug. 28, 1990, was just that for residents of Northern Illinois, with temperatures well into the 90s, triple-digit heat indices and blazing sunshine. That day, a fairly typical summer storm system generated strong thunderstorms across part of the upper Midwest, posing an apparent threat for heavy rain, damaging winds and hail.
The tornado risk that afternoon was rather low given the atmospheric profile as a whole, until a smaller-scale feature drifted in from Lake Michigan, a pool of cooler air taking the form of a localized cold front. The seemingly innocuous lake breeze unfortunately introduced a great deal of low-level spin in the atmosphere, allowing an isolated complex of storms to take full advantage of the environment.
A Severe Thunderstorm Warning was issued for the powerful supercell that spawned the killer tornado just after 3:15 p.m., with no tornado warning issued as it ransacked several western suburbs of Chicago, including Plainfield and adjacent areas. What seemed to be a run-of-the-mill summer storm to many turned into a hellacious nightmare for hundreds as the rain-wrapped tornado bore down without warning.
Nearly 30 lives were lost in the Plainfield tornado tragedy, and over 400 homes completely decimated, but countless lessons were also learned. After a federal investigation, series of lawsuits and wealth of in-depth meteorological studies, the disastrous late August tornado ultimately spurred advancements in forecasting and technology to ensure an oversight of this magnitude never repeats itself on American soil.
