STORY: While tornado outbreaks in the region are common, they are usually not as powerful as the one that ripped through Rolling Fork. "The Rolling Fork Mississippi tornado was extremely, extremely high above the 95th percentile for all significant tornadoes, which are EF2 or greater," Emmerson told Reuters on Saturday.Emmerson said two of the indicators of a powerful tornado are the height to which it lifts debris as well as its rotational velocity on the weather radar. The Rolling Fork tornado lifted debris upto 30,000 feet."In that subset of strong tornadoes, this was way, way up in the higher, higher parts of the distribution for both of those metrics. So it's a very, very high caliber, very intense tornado by most estimates," he said.