ROLLINGSTONE, Minn. – The tornado that made this Winona County community its epicenter was a mere EF-1 on the six-point Enhanced Fujita scale. A survey by the National Weather Service concluded that tornado winds were estimated at 105 mph. The tornado twisted down from storm clouds near St Charles on the Winona-Olmsted county line at 6:01 p.m. The centrifugal speed intensified over the eight miles to Rollingstone. Four miles farther it weakened while crossing the Mississippi River near Lock and Dam 5 and into Merrick State Park in Wisconsin. The path was as much as 50 yards wide.
Earlier: Roads cleared of storm-caused blockages
Earlier: Storm ruins two Rollingstone houses
Earlier: Photo gallery
Rating tornadoes
Weatherologist Theodore Fujita devised the scale bearing his name in 1971 at Texas Tech University for quantified comparisons. Ratings are based on three-second bursts.
> EF-0: 65 mph to 85 mph
> EF-1: 86 mph to 110 mph
>EF-2: 111 mph to 135 mph
> EF-3: 136 mph to 165 mph
> EF-4: 166 mph to 200 mph
> EF-05: Off the charts
Worst on record: 321 mph at Bridge Creek, Oklahoma, in 1999.