Powerful Storms!

Where do they usually occur?

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

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!

Hurricanes, Cyclones, Typhoons What’s the difference?

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)

Hurricane

Typhoon

Cyclone

Distribution

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

Why do they occur?

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

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.

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.

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

How do we Measure the Strength?

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

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!

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

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

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!

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!

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?

Tornado Alley, USA

Which States?

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

Kansas, Wizard of Oz!

What Causes Them?

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!

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.

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

EF0

EF1

EF2

EF3

EF4

EF5 (Finger of God)