Why does NW Arkansas have so many tornadoes? BY Claire Smith

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Why does NW Arkansas have so many
tornadoes?BYClaire Smith
EAST/EMPACTS INDEPENDENT STUDY

• C. Dianne Phillips, EAST/EMPACTS Facilitator

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INTRODUCTION

• Northwest Arkansas is in a section of the
  Southern region of the United States known for
  frequent tornado activity, tornado alley.

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• The local topography, in association with
  unstable air masses, fuels super-cell
  thunderstorms which have the potential for the
  formation of tornadoes.

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Community Aspect

• There is a need to provide information to the
  public . An informational Power Point is
  provided to raise awareness about the frequency
  and distribution of tornadoes.

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Course Content Objectives

• To learn..
• Why tornadoes occur in NW Arkansas
• What factors contribute to the formation of
  tornadoes
• Determine the location of tornado alley and the
  mechanisms that lead to its location.

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Tornado alley
What makes Arkansas a good conductor for severe
tornado activity?

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Meteorology Terms Remember

• Subtropical Climate- Climate zone with hot humid
  summers and chilly mild winters. Significant
  amounts of precipitation occur during all
  seasons, sometimes in excessive quantities.
• Humid Continental Climate- A zone located in the
  mid latitudes where there is conflict between
  polar and tropical air masses
• Supercells- Storm cells which may produce rain,
  hail, lightning, and dangerous bursts of wind.
  Rotating wind rises into the storm creating a
  mesocyclone and the ability for supercells to
  travel along the ground for long periods of time.
  
• Updraft- Air rising up into a thunderstorm

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3 conditions required for a tornado

• Moisture in the lower to mid levels of the
  atmosphere.
• Unstable air, which is air that rises from the
  ground and does not stop.
• A lifting force such as the unstable air if it is
  warm. Cooler air forces the warm air upwards and
  triggers thunderstorms.

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Conductors

• Arkansas shares a border with 6 states the
  eastern boarder primarily made up of the
  Mississippi river. Its unique geography makes up
  the United States interior highlands.
• The unique geography also creates a collision of
  several different air masses from surrounding
  areas and mountain regions such as the Ozarks,
  Ouachitas, the Gulf of Mexico, as well as the
  Mississippi river.
• This creates a big conflict between subtropical
  climate and continental climate especially in
  spring like weather conditions.
• Arkansas main weather conductor is the warm Gulf
  of Mexico.

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Conductors

• Although far enough away from the coast to be hit
  directly by a hurricane Arkansas gets the
  aftermath of a tropical system.
• Tropical systems come with very large amounts of
  rain in a short period of time sometimes causing
  massive floods.
• Tropical systems are also known for spawning
  smaller but dangerous tornadoes which travel up
  the coast line to what is known as tornado alley.
  

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Step by Step Formation of a Tornado

• Plenty of hot, humid air trapped beneath cold,
  dry air.
• The "cap," (the stable layer of air between the
  hot and  cold air) is disturbed. The disturbance
  can be caused by an upper-level air  disturbance,
  or the arrival of a front
• As the lower-level air rises, it expands in the
  reduced air pressure aloft  (air pressure drops
  as altitude increases), and it cools. Eventually,
  the  cooling causes the moisture to condense

• 4. Condensation releases latent heat, warming the
  air, making it buoyant, and  causing it to rise
  quickly (at speeds up to 150 mph). By now, the
  cloud has  formed into a thunderstorm.
  Upper-level winds tilt the thunderhead to create
  the anvil at the top.
• 5. The thunderstorm may die out in intense rain
  and/or hail. Or it may spawn a  tornado.

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Step by Step Formation of a Tornado

• 6. Interactions between air at various altitudes,
  humidity's and temperatures  causes rain,
  lightning, air circulation and an intensification
  of the rotating  updraft, called a "mesocyclone."
  Low-level wind helps cause this  rotation, which
  is almost always counter-clockwise
• 7. A tornado may form below the mesocyclone. As
  the spinning column of air  narrows, it rotates
  faster and extends higher into the storm. 
• http//video.google.com/videoplay?docid-407040663
  2797901470qmesocyclone20and20tornado20formati
  onhlen

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The Impact of a Natural Disaster Can Be
Devastating!

• Headlines, News Stories, Records

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The town of Dumas, Arkansas is a disaster
zone tonight. Power is out in the city and
rescuers have been working for hours to get
people help.

• Feb. 24th 2007

• Powerful Wind Storms, Tornado Wounds 40, Destroys
  Over 90 Homes in Arkansas

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Mountain View, AR

• http//www.youtube.com/watch?vuG82kA5JD4M
• http//www.youtube.com/watch?vuEVmCvA6ujcfeature
  related

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F5 Tornadoes, Moore, OK, 1999

• http//www.youtube.com/watch?v4pbqGsS5iB4

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Tornado Record Broken 1999
Baseball size hail

• there were 56 tornadoes produced statewide...a
  record for one outbreak.  The previous record was
  34 tornadoes on June 5, 1916.   It must be said
  that 56 tornadoes is incredible considering that
  Arkansas is normally affected by 21 tornadoes per
  year!      

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The late Dr. Fujitas Tornado Scale of Damage -

• ranked tornadoes according to the damage they
  left behind- F0least damage to F5greatest
  damage.

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Skills Developed

• Technology
• Microsoft Suite, Word, Power Point, Front Page
• Internet, uTube videos
• Time Management
• Organization
• Planning
• Presentation
• Power point design
• Research
• library, internet, national weather service in
  Tulsa, 40/29 meteorology archives.

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Acknowledgements/References

• 40/29 News, Steve Gibbs
• National Weather Service in Tulsa, OK
• Mountain View, AR Survivors
• Dumas Morning News
• Dr. Fugita
• C. Dianne Phillips, EAST/EMPACTS Facilitator