- Strong, persistent rotation in the cloud base.
- Whirling dust and or debris on ground underneath cloud base.
- Tornadoes do not always have visible funnels – can be rain wrapped.
- Hail or heavy rain followed by either absolute calm or extreme wind shift.
- Loud continuous roar or rumble unlike thunder that fades within seconds.
- Visible small, bright, blue and green to white power flashes at ground level.