1. WHY DOES NW ARKANSAS HAVE SO MANY TORNADOES? BY CLAIRE SMITH C. Dianne Phillips, EAST/EMPACTS Facilitator EAST/EMPACTS INDEPENDENT STUDY

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

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

4. 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.

5. 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 it’s location.

6. TORNADO ALLEY What makes Arkansas a good conductor for severe tornado activity?

7. 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

8. 3 conditions required for a tornado 1.Moisture in the lower to mid levels of the atmosphere. 2.Unstable air, which is air that rises from the ground and does not stop. 3.A lifting force such as the unstable air if it is warm. Cooler air forces the warm air upwards and triggers thunderstorms.

9. 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, Ouachita’s, 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.

10. 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.

11. Step by Step Formation of a Tornado 1.Plenty of hot, humid air trapped beneath cold, dry air. 2.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 3.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.

12. 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?d ocid=- 4070406632797901470&q=mesoc yclone%20and%20tornado%20for mation&hl=en

13. The Impact of a Natural Disaster Can Be Devastating! Headlines, News Stories, & Records

14. 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

15. Mountain View, AR http://www.youtube.com/watch?v=uG82kA5J D4M http://www.youtube.com/watch?v=uG82kA5J D4M http://www.youtube.com/watch?v=uEVmCvA 6ujc&feature=related http://www.youtube.com/watch?v=uEVmCvA 6ujc&feature=related

16. F5 Tornadoes, Moore, OK, 1999 http://www.youtube.com/watch?v=4pbqGsS5 iB4 http://www.youtube.com/watch?v=4pbqGsS5 iB4

17. Tornado Record Broken 1999 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!

18. The late Dr. Fujita’s Tornado Scale of Damage - ranked tornadoes according to the damage they left behind- F0:least damage to F5:greatest damage.

21. 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.

22. 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