High Quality Content by WIKIPEDIA articles! The Oak Lawn Tornado Outbreak was the tornado outbreak that occurred on April 21, 1967, across the Upper Midwest of the United States, in particular the Chicago area including the towns of Belvidere and Oak Lawn, Illinois. It was the most notable tornado outbreak of 1967 and one of the most notable to occur in the Chicago area. The Belvidere disaster was documented in an episode of The Weather Channel`s Storm Stories.