The National Weather Service says Monday's tornado in Pilger tornado appears to be an EF4, with estimated wind speeds of 166 to 200 mph.
Meteorologist Van DeWald says survey teams found several damage points that indicate an EF4 tornado, the second-strongest rating on the scale that measures tornado strength.
The National Weather Service says four tornadoes likely touched the ground during the massive storm in northeast Nebraska.
DeWald says the first tornado to touch down west of Stanton has damage that suggests a least an EF3 rating, with wind speeds of 136 to 165 mph. The first tornado is believed to have traveled 15 miles on the ground.
DeWald says crews are still surveying damage and haven't yet determined how long the Pilger tornado was on the ground.