Robinson lee
Member
1968 Charles City IA F5 tornado once had a similar spiral scouring. According to the spiral scouring, some scientists speculated that the wind speed of tornado reached 528 mph. The fact is that the tornado in Charles City, as F5, has no very impressive damage. There is a relationship between the scouring and the movement and shape of tornado, as well as the soil, vegetation and water characteristics of the soil. Some very weak tornadoes have the same obvious effect In fact, spiral scour like this is not uncommon, such as Washington IL on November 17, 2013, Delmont SD on May 12, 2015 and Greentown tornado on April 11, 1965I've seen you state this a couple of times. Do you actually have any studies showing so?