I've been on the edges of a few tornadoes, and seen the aftermath of a few more. You know you're close to the funnel cloud when the sky turns dark greenish gray and there's a sound like a passing freight train. Based on your pictures, there might have been funnel clouds closer than you know. If they didn't touch down, or weren't fully formed, then it would take Doppler radar to know if they ever existed.
It's just luck that the funnel cloud that took out the town next to yours didn't take out your school. Given that there was a probably tornado warning for your area, I'm surprised your school didn't declare an emergency and get everyone into the basement or at least onto the ground floors away from the windows. If a tornado had hit your school, you could have been killed or injured by flying glass from broken windows, or debris hurled through the windows.