On May 3 and 4, 1999, between sixty-six and seventy-four tornados occur in Oklahoma

It is the most prolific tornado outbreak in Oklahoma history. The worst begins in Chickasha on May 3, in the afternoon. The National Weather Service issues a severe thunderstorm warning for Tillman County at 4:15 p.m. But the thunderstorm rapidly develops supercell characteristics, threatening tornadic rotation. A tornado warning is issued on May 3 at 4:50 p.m. for Comanche, Caddo, and Grady counties.

This supercell’s first tornado touches down at 4:51 p.m. The first tornado is followed by four more, the largest of which is accompanied by a satellite tornado for several minutes.

But the worst of the tornados does not touch down until 6:23 p.m. Now it destroys the community of Bridge Creek, Oklahoma, and heads over Tinker Air Force Base into Oklahoma City, where it destroys over eight thousand homes, causing over a billion dollars in damages, its wind speeds reaching a detected 484 kilometers per hour. It crosses the Canadian River, I-44, I-35, and I-240, directly striking two overpasses.

Those on the road when the tornado appears assume that overpasses will protect them from the natural disaster, so they pull over underneath them and sit and wait. In fact, however, the massive concrete structures channel the wind, change its direction, increase its force. And all those seeking shelter beneath these two overpasses are killed.