2. Violent Weather Thunderstorms, Tornadoes Hurricanes, Etc.

3. Annual Number of Thunderstorm Days

4. Thunderstorms Formed either –Within an air mass when unequal heating causes warm air to rise -- or –Cold fronts(*) push warm air up quickly -- and –In both cases the water vapor condenses to form clouds. Unstable atmospheric conditions and release of latent heat from condensation causes more uplift and cumulonimbus clouds form. (*Warm fronts can sometimes cause this, but only in very unstable air with lots of moisture since the slope is more gradual.)

5. What causes Lightning? Lightning is electricity - the movement of electrons. Why do they move? Charges are 1 st separated in the cloud by friction. The positive charges go to the top of the cloud, leaving extra electrons behind in the bottom of the cloud. In cloud to cloud lighting these opposite charges attract and electrons move - lightning occurs.VideoVideo In order for lightning to strike the ground the ground must become charged. The ground is charged by induction – the negative charges in the bottom of the cloud push the negative charges away (Remember that like charges repel.) This causes the ground to become positively charged. Now the ground is + and the cloud bottom is -, and since opposites attract electrons now flow to the ground – LIGHTNING!VideoVideo

6. Coulomb’s Law Coulomb’s law tells us the amount of force of attraction (opposite charges) or repelling (like charges) between charged particles, like protons and electrons The formula is Fe = K (q1x q2)/d^2 Fe is force of attraction K is a constant q stands for the amount of the charge on each charged particle (q1 and q2) d is the distance between the charged particles So, the force of attraction or repelling between the two particles directly relates to the amount of charge they have And is inversely related to the square of the distance between them. (inverse square law again) So, are you more likely to be hit by lightning when the storm is closer or further away? Why? Are you more or less likely to be hit if the cloud has more charge built up? Why? -+

7. Lightning Safety LINK

8. TORNADOESTORNADOES

9. Damage Path from a Tornado

10. Tornadoes form most commonly in spring when temperature contrasts between cP and mT air masses are most pronounced. These large contrasts cause “supercells”, the worst storms which may cause violent storms and tornadoes. Average Tornadoes - WHEN?

11. Average Tornadoes per Year - WHERE? Large temperature contrasts occur in the midwest where cold cP air masses over the Rockies meet warm mT air masses from the Gulf of Mexico. This is Tornado Alley Video

13. Fujita Intensity Scale Number of Tornadoes-blue Amount of Damage-red Notice that most tornadoes are weak

15. Doppler Radar below shows the typical “hook” of tornado formation Tornado formation link

16. How the tornado forms

19. Tornadoes and Hurricanes

20. The strength of tornado winds! Tornado LINK Tornado LINK

21. Tornado Videos Hollywood shows us what to do in a tornado Biggest danger – debris Cows? And water spouts Real Tornado forming Real killer tornado Only in Hollywood

22. Hurricanes Notice counterclockwise motion of hurricane in Northern Hemisphere. It is a low pressure system.

23. Formation of Tropical Cyclones They form over warm ocean water, getting their heat from the warm water These low pressure disturbances form in the tropics of the N Atlantic, N Pacific, Indian and Western S Pacific (see map pg 342 in text.) The rising warm water vapor condenses, releasing latent heat, strengthening the hurricane - videovideo The hurricane breaks up over cold water or land when the energy source disappears

24. Tropical cyclone names and places Hurricanes in the eastern Pacific Ocean Rarely occur

25. Rare South American Hurricane. What do you notice? In the climate unit we will discuss this hurricane again and its possible causes.

26. Profile of a Hurricane

27. Notice stronger winds on NE side. Why?

28. Wind Speed Increases Toward Eye Just like this skater spinning. When she pulls her arms in her radius decreases and she spins faster.

29. Tropical Disturbances Tropical Depression < 39 mph Tropical Storm 39-74 mph Hurricane >74 mph Wind Speeds – when is it a hurricane?

31. Hurricane Damage Videos Eye wall Wind damage Hurricane Andrew damageHurricane Andrew damage What causes damage from hurricanes? Wind - videovideo Storm surge flooding Excessive Rain

33. Richelieu Apartments before Hurricane Camille

34. Richelieu Apartments after Hurricane Camille

36. And Katrina We’ve all seen the pictures

37. Katrina’s Damages Wetlands pumped – destroyedpumped – destroyed And what happened to those levees, built at the expense of the wetlands, to protect the city? videovideo

38. NY Hurricane? Can we have hurricanes in New York? What will the future bring? Video Planning and other hurricane information bookletPlanning and other hurricane information booklet New York Hurricane GIS

39. Hurricane TrackingHurricane Tracking hyperlink Mapping chart Mapping chart

40. Hurricane Path

42. Hurricane Allen 1980 Hurricane Detection & Tracking

43. Hurricane Andrew 1992

44. Hurricane movies The 27 storms of 2005 – streaming video Arlene to Zeta or go to link belowArlene to Zeta http://learners.gsfc.nasa.gov/mediaviewer/2 7Storms/http://learners.gsfc.nasa.gov/mediaviewer/2 7Storms/ http://www.classzone.com/books/earth _science/terc/content/visualizations/es2 008/es2008page01.cfm?chapter_no=vi sualizationhttp://www.classzone.com/books/earth _science/terc/content/visualizations/es2 008/es2008page01.cfm?chapter_no=vi sualization

45. Cold waves, blizzards Other weather disasters:

46. FLOODING of all types Mudslides can also kill and destroyMudslides (like Hurricane Mitch) Floods And MORE FLOODS Flooding is one of the most destructive occurrences from ALL weather disasters, and causes the most deaths. What is the other most damaging?

47. Effects of heats and droughts are often worst When we do the climate unit we will discuss why heat waves may increase.