Teams of experts surveyed damage from tornadoes that ripped through Iowa on Thursday and have concluded that two of the twisters produced winds of 144 mph, enough to cause severe damage in the cities of Marshalltown and Pella.
Survey crews determined that both tornadoes were rated EF-3, the fourth-most powerful kind of tornado on the Enhanced Fujita Scale.
- EF-0: 65-85 mph
- EF-1: 86-110 mph
- EF-2: 111-135 mph
- EF-3: 136-165 mph
- EF-4: 166-200 mph
- EF-5: 200+ mph
Marshalltown, specifically the northern side of the city of nearly 30,000, was struck by a large, wedge-shaped tornado just before 5 p.m. Thursday. At about the same time, a tornado also producing 144 mph winds, was ripping through Pella, a smaller town about an hour south of Marshalltown.
You can see damage photos obtained by the Des Moines office of the National Weather Service right here.
It's typical in EF-3 tornadoes to see well-built homes destroyed, severe damage to large buildings, train cars overturned, tree debarked, and vehicles thrown long distances.
Another tornado that struck just outside the northeast side of Des Moines, in Bondurant, produced low-end EF-2 damage with peak winds estimated at 115 mph.
All ratings are preliminary and the National Weather Service could change the rating as damage surveys continue.