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2. 1.Define Severe Weather 2. List 3 Examples

3. Thunderstorms
Right now there are about 2,000 thunderstorms occurring worldwide
There are about 45,000 thunderstorms per day!!
U.S. gets 100,000 per year! 3

4. 4

8. Severe Thunderstorms Torrential Downpours
Strong winds at greater than 58 mph
Hail ¾ inch diameter (or larger)
Frequent lightning

9. Severe Thunderstorm Watch
Issued by National Weather Service
This means that conditions are favorable for a thunderstorm
Length is multiple hours.

10. Severe Thunderstorm Warning
Issued By Local Weather Service
Means a severe storm has been spotted by doppler radar
Usually only an hour

11. 1. What state has the most lighting?
Lightning
1. What state has the most lighting?
2. How many people die from lighting in the US each year

12. Science of Lighting

13. 13

14. Types of Lightning Cloud-to-ground (CG) Intra-cloud (IC)
Ribbon lightning
Sheet lightning
Heat lightning
Ball lightning

15. Cloud-to-ground (CG) Lightning

18. Properties of a Cloud-to-ground Flash
Peak current of 30 to 40 kAmps
Temperatures of over 30,000°F
Channel diameter of 1 to 2 cm
Number of return strokes: 1 to 20 (avg ~4)

19. Properties of an Intra-cloud Flash
Much more frequent than CG flashes
Not well known (difficult to study)

25. Lightning Safety Stay indoors, away from doors and windows.
Do not take baths or showers.
Do not use phones with cords.

26. Cars are pretty safe…

27. Thunder

28. How Far Away Was That Lightning?
When you see the flash, start counting seconds.
When you hear the thunder, stop counting.
Every 5 seconds is equal to 1 mile.

29. Tornadoes

30. Birth of a Tornado

31. 1. What country has the most tornadoes?
2. How many people die in the US from tornadoes each year?

34. F-Scale

35. F-Scale F0 – Light damage F1 – Moderate damage
F2 – Considerable damage
F3 – Severe damage
F4 – Devastating damage
F5 – Incredible damage (Auntie Em!)

38. Tornado Watch
Conditions are favorable for a tornado to form

39. Tornado Warning
A tornado has formed nearby.

40. Tornado Safety Get indoors and stay there
Stay away from doors and windows
Get to lowest level possible
Don’t get near things that can fall on you

41. Tornado Safety

42. Hurricanes

43. What is the wind speed for a hurricane?
When do they form?
What is the wind speed for a hurricane?
What is the most dangerous part of the storm?

44. Formation Regions

45. Typical Paths

46. When to expect Hurricane season is June through November
Peak is in September

47. Formation of Hurricanes
Tropical Depression
Tropical Storm
Hurricane

48. Where do hurricane storms start? What is the coriolis effect?

49. Tropical Depression Cluster of organized thunderstorms
Not very compact
Sustained winds of at least 30 mph
Given a number

50. Tropical Storm Winds above 39 mph Given a name More organized
If hits land, most damage caused is by rainfall.

51. Hurricane Winds over 74 mph Well defined center of circulation
Eye Wall
Damage from includes:
Wind
Storm surge
Rain

52. Pressure in hurricane
A way to tell strength of hurricane is by its pressure
Measured in millibars (mb)
Higher pressures are weak, lower are stronger

53. Naming System A list of names from A-W (excluding Q)
Alternate from male to female
6 lists, repeated in cycle
Big name storms replaced 53

54. Saffir-Simpson Scale Designed by Herbert Saffir and Bob Simpson
Divides hurricanes into categories based on maximum sustained winds.

55. Wind Speed

57. Category 1 Winds- 74-95 mph Storm Surge- 4-5 ft. Pressure- 986mb
Damage- mobile homes, trees, minor coastal flooding 57

58. Category 2 Winds- 96-110 mph Storm surge- 6-8 ft.
Pressure mb
Damage- Some roof and window. Damage to piers on coast. Small crafts. vegetation

59. Category 3 Winds- 111-130 mph Storm surge- 9-12 ft.
Pressure mb
Damage- structure damage to homes and buildings. Mobile homes destroying. Major coastal flooding with a potential for inland flooding.

60. Category 4 Winds 131-155 mph Storm surge- 13-18 ft.
Pressure mb
Damage- Complete roof damage. Major erosion to beaches. Further inland flooding.

61. Category 5 Winds- Greater than 156 mph Storm surge- over 19 ft.
Pressure- less than 920 mb
Damage- Roofs torn off, buildings collapse, major inland flooding.

62. Hurricane Watch
A hurricane poses a possible threat within the next 36 hours

63. Hurricane Warning
Hurricane conditions expected within 24 hours

64. Most Damaging Storms 1) Katrina (2005)- 75 billion
2)Andrew (1992) 34 billion
3)Charley (2004)- 14 billion
4) Ivan (2004)- 13 billion
5) Wilma (2005)- 12 billion
..9) Agnes billion

65. Hurricane Safety Best plan is to evacuate Plan early in advance
Towns have voluntary evacuation during a watch, and some switch to mandatory during a warning.
Plan early in advance

66. IF you choose to stay Board all windows
Prepare Flashlights, avoid candles
Stay tuned to radio
Stay indoors 66