What is a tornado?
Rapidly rotating narrow column of air that is in contact with the surface of the earth and the cumulonimbus clouds of a thunderstorm.
- Winds usually about 100mph
- Usually last a few minutes
Describe the formation of a tornado.
1) Hot moist and cold dry air mass meet.
2) Supercell thunderstorm forms, with a well-defined rotating updraft circulation; a mesocyclone.
3) Wind shear creates this rotation.
4) Heavy rainfall drags down a column of air, dragging down the mesocyclone vortex.
5) The mesocyclone funnel spins at great speeds, bringing in warm, humid air, which condenses to form a wall cloud.
6) The updraft of warm air grows in intensity, creating a rapid pressure difference at the bottom.
7) The tornado is formed when the funnel cloud touches the ground.
8) Once touching the ground, it may pick up dirt and debris.
9) It will continue to grow whilst having warm, humid air, which releases latent heat when condensing.
10) It loses energy when cold air spreads and cuts off the warm air.
What are the hazards from a tornado?
- Strong winds
- Debris
- Associated storm hazards, eg lightening, hail, rain.
Give two eggs of a tornado.
Moore, Oklahoma 2013
* Destroyed 2 primary schools
* $2 billion damage
* Horses tossed in air
* Boy killed himself from PTSD
Tangail, Bangladesh 1996
* 2nd highest death toll on record
* Over 80 villages destroyed
* People buried alive under collapsed houses
How can tornadoes be managed?
- Satellite imagery to display data so forecasters can identify dangerous weather.
- NOAA can measure areas at risk.
- Storm spotters have been trained to recognise tornado conditions and report what they see to National Weather Service.
- Meteorologists can monitor Doppler radar and other features which are associated to tornadoes. They can then issue daily forecasts if conditions develop where tornadoes may form
- Tornado warnings given when a tornado has been sighted or indicated by weather radar
- Bunkers to hide in and stronger build buildings, although tornadoes can often still tear through
Where are tornadoes distributed?
- Most in USA
- Found across all continents
- Many in North America
- UK has many considering small size
