1. Welcome Back! 10/8/2012 1.How does a thunderstorm form? 2.How is lightning produced? 3.What type of clouds are associated with thunderstorms? 4.What has to happen in order for thunder to be produced? 5.What did you do this weekend? DO NOW!

2. LEQ 8 How do conditions in the upper and lower atmosphere cause tornadoes to form?

3. Activator STORMSTORM chasers 2 MINUTES 2 MINUTES - Think, Pair, Share: Share your initial reactions after watching this clip.

4. What are they? A VIOLENT, ROTATING column of air that is in contact with the surface of the earth and a CUMULONIMBUS cloud.

5. How do they form?form In unusually violent thunderstorms called SUPERCELLS.

6. How do they form?form Tornadoes need 2 things to form: – I NSTABILITY : Warm & humid conditions in the lower atmosphere and cooler than usual conditions in the upper atmosphere. – W IND SHEAR : Wind direction changing and the wind speed increasing with height.

7. S CALE W IND S PEED D AMAGE F0 40-72 MPH Light damage – Chimneys, branches down, trees pushed over F1 F2 F3 F4 F5

8. Bigger doesn’t always mean badder!

9. S CALE W IND S PEED D AMAGE F0 40-72 mph Light damage – Chimneys, branches down, trees pushed over F1 73-112 mph Moderate damage – Mobile homes pushed off foundations, cars moved off roads, peels surface off roofs F2 F3 F4 F5

10. Common F1 damage…

11. S CALE W IND S PEED D AMAGE F0 40-72 mph Light damage – Chimneys, branches down, trees pushed over F1 73-112 mph Moderate damage – Mobile homes pushed off foundations, cars moved off roads, peels surface off roofs F2 113 – 157 mph Significant damage – Roofs torn off, mobile homes demolished F3 F4 F5

12. F2 Damage

13. S CALE W IND S PEED D AMAGE F0 40-72 mph Light damage – Chimneys, branches down, trees pushed over F1 73-112 mph Moderate damage – Mobile homes pushed off foundations, cars moved off roads, peels surface off roofs F2 113 – 157 mph Significant damage – Roofs torn off, mobile homes demolished F3 158 – 206 mph Severe damage – Walls torn off, trains overturned, most trees in forest uprooted, cars thrown F4 F5

14. S CALE W IND S PEED D AMAGE F0 40-72 mph Light damage – Chimneys, branches down, trees pushed over F1 73-112 mph Moderate damage – Mobile homes pushed off foundations, cars moved off roads, peels surface off roofs F2 113 – 157 mph Significant damage – Roofs torn off, mobile homes demolished F3 158 – 206 mph Severe damage – Walls torn off, trains overturned, most trees in forest uprooted, cars thrown F4 207 -260 mph Devastating damage – Houses leveled, structures blown away F5

15. S CALE W IND S PEED D AMAGE F0 40-72 mph Light damage – Chimneys, branches down, trees pushed over F1 73-112 mph Moderate damage – Mobile homes pushed off foundations, cars moved off roads, peels surface off roofs F2 113 – 157 mph Significant damage – Roofs torn off, mobile homes demolished F3 158 – 206 mph Severe damage – Walls torn off, trains overturned, most trees in forest uprooted, cars thrown F4 207 -260 mph Devastating damage – Houses leveled, structures blown away F5 261 – 318 mph Incredible damage – Houses lifted off foundations and carried away, trees debarked