1. Powerful Storms!

2. Where do they usually occur?

3. Part 1: Tropical Storms The atmosphere is in continual motion!
With swirling masses of air that create our weather.
The movement of air masses happens for 2 major reasons:
1. The Earth spinning in daily rotation
2. Earth’s surface is unevenly heated

4. Tropical Storms As a result, POWERFUL STORMS sometimes occur!
Tropical Storms called Hurricanes, Cyclones, or Typhoons as the largest examples of Tropical Storms
Others storms such as Tornadoes and Blizzards also have the potential to destroy human property and life!

5. Hurricanes, Cyclones, Typhoons
What’s the difference?

6. All the Same! Only difference is the Location where the storm occurs!
Hurricanes: Atlantic and Northeast Pacific Oceans (Canada, USA)
Typhoon: Northwest Pacific (China, Vietnam, Indonesia)
Cyclone: South Pacific and Indian Ocean (Australia, India, Africa)

7. Hurricane

8. Typhoon

9. Cyclone

10. Distribution

11. Tropical Storm
Essentially a massive and violent rotation (spinning) of air and atmosphere
Middle is the Eye of the storm!

13. Why do they occur?

14. Begin at Equator Centre of the Earth’s Crust The Warmest part!
Then move either North or South towards COOLER regions.

16. Why does the Storm Happen?
Originate from Warm Ocean waters.
Think of them as Swirling Mountains of WARM and MOIST air heated by the sun.
As this warm air rises from the Ocean surface, Cooler air blows into the base of the air mass.

17. Why does the Storm Happen?
This causes a Tropical Disturbance
As the new air is heated and rises, the tropical disturbance grows larger and spins faster!
If it gets large, it’s upgraded to Hurricane status.

21. Movement Tropical storms then move outward from warm ocean regions.
This is why although they begin in Tropical areas, they can reach places such as the USA and even Canada!
However, the further they travel, the more they die out and eventually fade completely

23. How do we Measure the Strength?

24. Height of Storm Surge (m)
Saffir-Simpson Scale
Category
Wind Speed (km/h)
Severity
Height of Storm Surge (m) 1
75 to 152
Weak
1.2 to 1.5 2
153 to 176
Moderate
1.8 to 2.4 3
177 to 208
Strong
2.7 to 3.67 4
209 to 248
Very Strong
3.9 to 5.4 5
Above 248
Devastating
Above 5.4

25. Storm Surge
The Storm Surge is the sudden rise in sea level caused by the high winds pushing the water towards coastlines.
It’s like a Continuous Tsunami, though not as high!

27. Part 2: Tornadoes
What are they?
Where are they most likely to occur?

28. Tornadoes
People often confuse Tornadoes with Tropical Storms but they are different!
Tornado Season: Spring and Summer
Tropical Storm Season: Summer and Autumn

29. Tornadoes
Tornadoes also develop over Land while Tropical storms develop over Water.
Tornadoes will actually “fizzle out” if they go over a lake and suck up water
This is why they usually occur in flat, dusty places far away from lakes and oceans!

30. Tornadoes They Drop Down from clouds rather than arriving on land.
They have a distinct Spiral and are much smaller, tighter, and Faster Spinning than Hurricanes.
Tornadoes happen over the world, but MOST happen in the USA about 1200 a year!
100 in Canada!

31. Canada
In the 1980’s, “Twisters” as they were called tore into Canadian cities such as:
Barrie, Ontario
Edmonton, Alberta
Killing a total of 38 people!
What part of the USA has the most?

32. Tornado Alley, USA

34. Which States?

35. Tornado Alley, USA Texas Oklahoma Kansas South Dakota Illinois Iowa
Missouri
Nebraska
Colorado
North Dakota
Minnesota

36. Kansas, Wizard of Oz!

38. What Causes Them?

39. Tornado Cause When Warm Humid Air and Colder Air move close together.
Often happen during the North American Spring when Hot, moist air from the “Gulf of Mexico” flows North while Colder Arctic Air is still hanging around!
As humid air rises during the daytime, columns of colder air rush to the ground to take its place!

40. Tornado Causes
Sometime, the rising Warm air begins to Rotate around a Cold air column.
This forms a Funnel of spiralling warm air called a Vortex.
These are the rapid winds of the Tornado.

42. Type of Damage Frequency Percentage of Tornadoes
How do we Measure Them?
The Enhanced Fujta (EF) Scale
Rating Scale
Wind Speed (km/h)
Type of Damage Frequency
Percentage of Tornadoes
EFO
104 – 136
Minimal 28
EF1
137 – 176
Moderate 40
EF2
177 – 216
Significant 24
EF3
217 – 264
Severe 6
EF4
265 – 320
Devastating
1 to 2
EF5
Over 320
Incredible
Less than 1

43. EF0

44. EF1

45. EF2

46. EF3

47. EF4

48. EF5 (Finger of God)