- Rotating column of air
- In contact with the surface
- Hanging downward from a cumuliform cloud
- Often observable as a funnel cloud or circulating debris/dust at the ground
- Most intense of all atmospheric circulations, more so than Hurricanes
Tornado Characteristics §
- Size: 150-4000 meters wide
- Winds: 50-100 meters per second
- Difficult to observe
- Doppler radar estimates
- Duration: ~10 minutes to 1 hour
- Path length: ~10 kilometers
- Tri-State Tornado (1925 MO/IL/IN) 352 kilometer continuous path length (695 deaths)
- Tornadoes are rated based on the damage that they cause on the Enhanced Fujita scale (EF)
- Most tornadoes are EF-0 to EF-2 range. All are dangerous, regardless of strength
- Tornado Occurrence and distribution
- US experiences the most tornadoes, averaging around 1200 tornadoes per year
- Can occur any time during the year, most common in spring
- Can occur any time of day, most common from 3-7 PM
- Tornadoes do happen around the globe, although WAY more in the US. Europe has some tornadoes, other than that its just sparse
- More tornadoes were observed in recent decades
- This is due to a variety of things, not really global warming
- Doppler radar
- Increasing awareness
- A lot of tornadoes are weaker
- Theres no trend in strong tornadoes
- Chances are there were also lots of weaker tornadoes in the past, they just weren’t found or tracked or archived etc. The increase of number of tornadoes is more because of awareness and improvements in tech
- 2011 was such an outlier year that its often taken out of studies
Doppler Radar §
- As precipitation moves toward or away from the antenna, the returning radar pulse will change in frequency when compared to the transmitted frequency
- Allows us to determine wind speed towards/away from radar (radial wind)
- Polarimetric radar that transmits both a horizontal and a vertical radar pulse
- Allows us to better estimate shape and size of particles, precipitation rate
Tornado Checklist §
