During a performance of a nationally-known traveling circus, a severe thunderstorm developed and moved rapidly across the area. Strong winds from the storm caused a portion of the big-top to collapse, injuring more than a dozen spectators, some of them seriously. Attorneys for the injured plaintiffs filed suit, claiming negligence on the part of the circus company for the way that the big-top tent was put up, and also for failure to monitor forecasts for the possibility of severe weather.

Plaintiffs’ attorneys presented evidence in the form of surface weather observations from local airports, which indicated that the storms that day produced wind gusts as high as 57 mph. The winds, they claimed, were high, but not high enough to cause the damage and collapse of the circus tent, had it been properly constructed and secured.

Attorneys representing the defendant circus company came to COMPUWEATHER for a more detailed, pin-point look at the storms which occurred on that day in southern Minnesota. Forensic meteorologists went to work, obtaining not only the same data which plaintiff’s attorneys had presented, but also images of Doppler radar for the area, at 15 minute increments from the time the thunderstorm developed, until the time it had passed the area where the circus was being held. And it was the radar images which told the tale. The parts of the line of thunderstorms which passed over the nearby airport observing locations were much weaker than the part that went over the circus location. In addition, that part of the storm underwent “explosive strengthening” no more than five minutes before striking the area. At nearby airports, the highest winds observed were 57 mph. But at the site of the circus, radar measurements and estimates of the downdrafts coming out of the thunderheads indicated a high probability that winds were in excess of 90 mph, and possibly as high as 120 mph. COMPUWEATHER meteorologists examined severe weather advisories and statements issued by The National Weather Service for that afternoon. While they were somewhat accurate in forecasting the chance for severe weather, they were lacking in emphasizing the true severity of the storms which occurred.

Since the storms were of unusual and extraordinary strength, striking with little advance warning, even a tent which was properly constructed and secured (as the circus claims it was) stood little chance of holding up. Based on this information, the two parties were able to reach a settlement prior to trial. The settlement was one which attorneys for the circus termed as “much more favorable for our client, thanks to the detailed information provided by COMPUWEATHER “.