Chapter 20: Severe Storms

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Chapter 20 Severe Storms

• Tornadoes
• Hurricanes

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Hurricanes!!
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2010 - 2015 Atlantic Hurricane Names
2010 2011 2012 2013 2014 2015
Alex Arlene Alberto Andrea Arthur Ana
Bonnie Bret Beryl Barry Bertha Bill
Colin Cindy Chris Chantal Christobal Claudette
Danielle Don Debby Dorian Dolly Danny
Earl Emily Ernesto Erin Edouard Erika
Fiona Franklin Florence Fernand Fay Fred
Gaston Gert Gordon Gabrielle Gonzalo Grace
Hermine Harvey Helene Humberto Hanna Henri
Igor Irene Isaac Ingrid Isaias Ida
Julia Jose Joyce Jerry Josephine Joaquin
Karl Katia Kirk Karen Kyle Kate
Lisa Lee Leslie Lorenzo Laura Larry
Matthew Maria Michael Melissa Marco Mindy
Nicole Nate Nadine Nestor Nana Nicholas
Otto Ophelia Oscar Olga Omar Odette
Paula Philippe Patty Pablo Paulette Peter
Richard Rina Rafael Rebekah Rene Rose
Shary Sean Sandy Sebastien Sally Sam
Tomas Tammy Tony Tanya Teddy Teresa
Virginie Vince Valerie Van Vicky Victor
Walter Whitney William Wendy Wilfred Wanda
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At the surface, circulation is inward with a
strong cyclonic (counterclockwise) flow, much
like a giant whirlpool. In such warm core
cyclones, upward flow is strongest along the eye
wall and the eye itself is an area of sinking
air. In the upper atmosphere, rising air flows
outward.
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Hurricane Structure                            
                                                  
                                                  
                                                  
                                                  
             
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Eyewall
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Hurricane Formation
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Tornado

• Violent windstorms that take the form of a
  rotating column of air called a vortex.
• The vortex extends downward from a cumulonimbus
  cloud.

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Tornado
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Tornado Safety
DURING A TORNADO Go to a basement. If you do not
have a basement, go to an interior room without
windows on the lowest floor such as a bathroom or
closet. If you can, get under a sturdy piece of
furniture, like a table. If you live in a mobile
home get out. They offer little protection
against tornadoes. Get out of automobiles. Do not
try to outrun a tornado in your car, leave it
immediately. If youre outside, go to a ditch or
low lying area and lie flat in it. Stay away from
fallen power lines and stay out of damaged areas.

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 Fujita Scale of Tornado Intensity
            
SCALE WIND SPEED POSSIBLE DAMAGE
F0  40-72 mph Light damage Branches broken off trees minor roof damage
F1 73-112 mph Moderate damage Trees snapped mobile home pushed off foundations roofs damaged
F2 113-157 mph Considerable damage Mobile homes demolished trees uprooted strong built homes unroofed
F3 158-206 mph Severe damage Trains overturned cars lifted off the ground strong built homes have outside walls blown away
F4 207-260 mph Devastating damage Houses leveled leaving piles of debris cars thrown 300 yards or more in the air
F5 261-318 mph Incredible damage Strongly built homes completely blown away automobile-sized missiles generated
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• Know the Lingo
• TORNADO WATCH - Tornadoes are possible in your
  area. Stay tuned to the radio or television
  news.TORNADO WARNING - A tornado is either on
  the ground or has been detected by Doppler radar.
  Seek shelter immediately!

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When are tornadoes most likely to occur?

• Tornadoes can happen at any time of the year and
  at any time of the day.
• Peak times for tornadoes in the northern states
  are during the summer.
• Tornadoes are most likely to occur between 3 p.m.
  and 9 p.m.

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HURRICANES AND TORNADOES
What's the difference?
Hurricanes and tornadoes both form in warm, damp
air when winds blow into each other from opposite
directions. Hurricanes develop over warm,
tropical oceans, while tornadoes form over land
and are more violent. In a hurricane, the winds
swirl around in a spiral at up to 200 mph. In the
middle is a calm "eye" 4 - 25 miles wide,
surrounded by the worst wind and driving rain.
A tornado is a tall, funnel-shaped whirlwind of
cloud up to 2,000 feet high. In the middle is an
eye of descending air, surrounded by a strong
upward current that sucks up or destroys
everything in its path. Tornadoes can travel
hundreds of miles before they die down.
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How Do Hurricanes Get Their Names? Hurricanes
have been given names since the early 1900s, when
an Australian weatherman would give names to the
storms he tracked to help keep them apart. He
enjoyed naming them after politicians he didn't
like, so that he could then talk about the
destruction that they caused.When the US Army
got heavily into weather forecasting during World
War II, workers there would start to nickname the
storm systems after their wives or girlfriends,
to give them their 15 minutes of fame. Soon they
began to start with A and move through the
letters, to make tracking the systems easier. By
1953 this was standard for the US Weather Bureau.
In 1970 the National Weather Service had this
responsibility, and moved to include men's names
as well.Names are chosen for 6 years in a row,
and then cycle around to the first set of names
again. If a storm is truly memorable, that name
is retired and a new one chosen to take its
place.
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• Myth or Misconception 1 .... Tornadoes never
  strike big cities.
• Myth or Misconception 2 .... Opening windows to
  equalize air pressure will save a roof, or even a
  home, from destruction by a tornado.
• Myth or Misconception 3 .... Highway overpasses
  are a safe place to shelter if you are on the
  road when you see a tornado coming.

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