1. Tornadoes

2. What is a Tornado?
-A rapidly rotating column of air that is touching the ground and a cumulonimbus cloud
-Generally have wind speeds less than 110 mph with a diameter of feet but the most powerful can have wind speeds of over 300 mph and a diameter greater than two miles

3. Contrasts between small and large tornado

4. Formation
-90 second clip
1:30-3:08

5. Life cycle
A typical tornado forms from a powerful thunderstorm known as a supercell
Once a tornado has formed it will thrive until it loses its source of warm air
As a tornado weakens, it will become thin and start to stretch wildly as it becomes ropelike
The system may dissipate at this point or it may reform a tornado
A single system may go through this cycle multiple times

6. Life cycle

7. Tornado Alley Area of high tornado frequency and magnitude
The lack of mountains allows warm air from the south to mix with cool air from the north which can violently mix together creating storms and conditions that allow tornadoes to form

8. Tornado Facts
Tornadoes may travel a few miles or up to several dozen miles depending on the tornadoes strength and conditions
Powerful updrafts create an area of low pressure at the surface which have been measured at 850 mb in one powerful tornado1
Low pressure causes water to condense into cloud droplets through adiabatic cooling creating the iconic funnel cloud of a tornado

9. Tornado Facts
Some tornadoes do not have a funnel cloud but will still have dust and debris within them that somewhat resembles a funnel cloud
The tornado itself often extends beyond a funnel cloud, as long as an area has the wind patterns of a tornado, it is part of the tornado
Tornadoes can reach the ground before a descending funnel cloud reaches the surface

10. Tornado without a funnel cloud

11. Preparing before a Tornado
Have a plan made up prior to the tornado
Make a first aid kit with things you may need
Water
Flashlight
Radio
Blankets
FIre extinguisher
Have “safe” rooms planed out
Get to a safe room quickly and stay as low as possible to ground
Have a destination outside of your home to meet up incase you get separated during tornado or storm

12. Tornado Safety Move to underground shelter or basement if possible
No basement available, small interior rooms with no windows
Hallways on the lowest part of the building
Avoid sitting by windows, and large objects such as dressers
If none of these work try and get to a vehicle, wear seat belt
Listen for updates on a radio or TV
Stay safe until updates are given that it is safe to get out
Put kids or infants in car seats or carriers
Cover with any pillows and blankets

13. If outdoors Try to find closest building
Get to your vehicle if last option
Stay away from bridges and higher ground
Watch out for debris getting thrown
If winds are very strong and there is flying debris while driving:
Pull over
Keep car running
Keep seat belt on
Cover head with coat/ blanket and stay below the windows
Flat areas outside are the best if you have to be outside
Lie face down, flat on ground with arms over your head

14. Tornado Classification
Developed by DR. Theodore Fujita in 1971
Based off estimated wind speeds and damage to an area
5 categories; F0-F5
F mph, light damage, tree branches broken
F mph, Moderate damage, mobile homes flipped
F mph, Considerable damage, mobile homes demolished, trees uprooted
F mph, severe damage, roof and walls torn down, flipped vehicles
F mph, devastating damage, well constructed walls leveled
F mph, violent damage, homes lifted off foundation, thrown as far as 100 m

15. Enhanced Fujita Scale

16. Cont. Very similar to original scale
Damage Indicators are used to help estimate wind speeds and distinguish between degree of damages

17. EF-1 damage vs. EF-5 damage
Expressed a “F” or “EF”
Fujita and Enhanced Fujita
Safety Video `

18. Sources
1 Julian J. Lee; Timothy P. Samaras; Carl R. Young ( ). "Pressure Measurements at the ground in an F-4 tornado". Preprints of the 22nd Conf. Severe Local Storms. Hyannis, Massachusetts: American Meteorological Society.

19. Questions?