Experts rank Saturday's twister as an F-4. Nebraska has only had two tornadoes in its history of this strength.
UNL Climatologist Ken Dewey was just outside of Hallam Saturday night chasing the storm.
"All we could see was lightning behind it. It just looked like a huge cloud touching the ground, that was the tornado."
Dewey says there was one giant tornado, at one point 2.5 miles wide, with several mini twisters inside. At a moment, the entire town of Hallam was inside it.
"It was very long lived," says Dewey.
The tornado's path covered 52 miles. It began in Daykin, and grew in intensity as it moved through Western and Swanton. By the time it reached Wilbur, the twister grew to an F2. After hitting Claytonia the twister was at its most intense stage, an F4. That's when it crossed over to Hallam. Next on to Norris where it destroyed the high school. It then gradually weakened as it passed Holland and Bennet. Then finally the twister dissipated near Palmyra.
Experts estimate wind speeds reached between 207 and 260 miles an hour in Hallam Saturday. Climatologists say there are only a few places in the U.S. where a tornado has completely engulfed a town.