Strong, persistent rotation in the cloud base. Whirling dust or debris on the ground under a cloud base -- tornadoes sometimes have no funnel! Hail or heavy rain followed by either dead calm or a fast, intense wind shift. ... These mean power lines are being snapped by very strong wind, maybe a tornado.
What are the six signs of a tornado?
- The color of the sky may change to a dark greenish color.
- A strange quiet occurring within or shortly after a thunderstorm.
- A loud roar that sounds similar to a freight train.
- An approaching cloud of debris, especially at ground level.
- Debris falling from the sky.