Severe Weather

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Severe Weather

• Notes and information

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BIG IDEA

• The root of all weather is the Sun, which heats
  the Earth. The heating is uneven, because of
  night and day, because different surfaces (such
  as rocks and trees) absorb and reflect sunlight
  in different amounts, and because sunlight hits
  the equator more directly than the poles. Uneven
  heat creates pressure differences, and wind flows
  between areas of high and low pressure.

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Thunderstorms
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storms
Thunderstorm is storm with thunder, lightning,
heavy rains and strong winds form within large
cumulonimbus clouds usually form along a cold
front but can form within an air mass. Click on
the links below
Thunderstorm Formation Animation
Real Thunderstorm Animation
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How they Form

• Form within large cumulonimbus clouds.
• Warm air is forced upward by a cold front.
• Warm air rises extremely quickly cools and
  condenses just as fast to form huge dense clouds
  (anvil).

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Characteristics Lightning and Thunder

• Positive and negative charges build up in clouds.
• Lightning is a sudden spark as charges jump from
  one cloud to another.
• Thunder is caused by the rapid heating of the air.

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Characteristics When and Where?

• Most Likely to form on hot humid days
• Spring and Summer
• Occur in areas where cold fronts are common
• (just about anywhere)

• To be severe it must have ONE OR MORE of the
  following
• Winds at least 57.5 mi/hr
• Hail ¾ or larger
• Tornado

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Thunderstorm Safety

• Avoid metal objects
• Try not to be the tallest object in an area
• Find a low area away from trees, fences and
  poles.
• Make yourself as small as possible.
• Stay out of the water
• Avoid touching electrical appliances or phones.

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Interesting Facts

• You can calculate your distance from a storm.
• of sec. / 3 s/km distance(km)
• Lets Try
• At any given time there are 1800 storms on Earth.
• 80 die from lightning each yr.
• Winds can exceed 160 km/hr.
• Causes hundreds of millions of in damage each
  yr.

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Tornadoes
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storms

• A tornado is a rapidly whirling, funnel-shaped
  cloud that extends down from a storm cloud the
  very low pressure and strong winds can cause
  great damage to people and property.
• Tornadoes are likely to form within the frontal
  regions where strong thunderstorms are also
  present.
• Click on the link below to do the animation

Tornado Wind Patterns Animation
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How They Form

1. Develop in low heavy cumulonimbus clouds.
2. Warm air rises so fast that it creates an
   updraft.
3. As it rises it begins to rotate
4. At the same time, cold air drops just as fast and
   creates a downdraft
5. Updraft grows more narrow, and spins faster.

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Another view
Play Animation
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Where and When(characteristics)

• Occur in Spring or Summer
• Associated with
• T-Storms
• Tornado Alley.

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Tornado Alley

• The Great Plains
• Why?..........
• Warm, moist air from the Gulf rises and meets
  with cold dry air from Canada.

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Interesting Facts

• Wind speeds can reach up to 480 km/hr.
• More common in US than any other country
• Biggest threat is flying debris

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Tornado Safety

• Tornado watch they are possible
• Tornado Warning one has been seen
• Go to the basement of a well-built building.
• Stay away from windows and doors
• Lie under a steady piece of furniture
• Duck and cover
• If outside lie in a ditch

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Now.Some cool pictures
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Hurricanes
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storms

• A hurricane is a low pressure tropical storm that
  forms over warm ocean water winds form a
  spinning circular pattern around the center, or
  eye, of the storm.
• The lower the air pressure at the center, the
  faster the winds blow toward the center of the
  storm.
• Click on the link to watch the video

Hurricanes 101 Video
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How they form

• Begins over warm water in a low pressure area
• Warm humid air from ocean water rises to form
  clouds
• Winds spiral inward toward low pressure.

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When and Where Characteristics

• Forms in the summer and fall over the oceans
• Winds can be as strong as 320 km./hr.
• Last a week or more
• Loses strength after reaching land.
• Play animation

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Special Features Characteristics

• The eye is the center of the hurricane which has
  very calm weather.
• Storm Surge huge rush of water that arrives with
  hurricanes.

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Saffir-Simpson Scale

• category 1 minimal (119-153 km/h)
• category 2 moderate (154-177 km/h)
• category 3 Extensive (178-209 km/h)
• category 4 Extreme (210-250 km/h)
• category 5 Catastrophic (over 250 km/h)

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Hurricane Safety

• Hurricane watch conditions are possible
• Hurricane warning conditions are expected.
• Evacuate the area
• Move to the interior of a building away from
  windows.
• Stay well above sea level

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Interesting Facts

• Typical hurricane is 600km. Across
• (Andrew was only 60 km)
• Hurricane Andrew cost over 25 bill.
• Andrew was only 1 of 3 that hit the US to be
  classified as a category 5 hurricane
• In the Pacific it is called a typhoon

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The End