From NBC2:

Cameras inside a school have allowed us to get an inside look at the power of an EF 4 tornado that destroyed towns from Pekin, Illinois to Henryville to Marysville, Indiana earlier this month.

Surveillance cameras inside Henryville Junior Senior High School were rolling as the storm destroyed their building.

Everything looked fine from outside Henryville Junior Senior High School just after school let out at 3 p.m. on Friday March 2, but as the buses pull back in and teachers come running out of the building to get the kids inside you start to understand that something dangerous is not far away.

In the background Henryville Auto Sales is still standing and that cafe where the bus ended up is still in one piece.

Just about four minutes after the last students got into the building the tornado hits and the cameras go black.

“The amount of energy and destruction that took place in such a short amount of time really boggles the mind,” Assistant Superintendent Dr. John Reed said as he watched the video.

From the south end of the building near the playground the camera stays on as the tornado rips off the roof in the pieces.

It all happens in no more than 20 seconds.

About 80 staff and students were in the building at the time.