A violent tornado that tore through part of North Dakota this past June was a monster - no one disputed that. It was a mile wide with whirling winds so strong it pushed more that 30 train cars off their track and caved in metal silos.

But the full power of that storm wasn’t known until this week, when the National Weather Service with the help of tornado researchers classified the twister as a deadly EF-5 with peak winds of 210 mph. The U.S. has not seen a tornado that strong since 2013.

The damage survey showed the tornado struck just after 11 p.m. on June 20 and was on the ground for less than 20 minutes. It traveled 12 miles and ripped through a river valley with such force that it debarked trees with a “sandpapering” effect.

“In the last ... 12 years, there’s been several strong t

See Full Page