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Lightning

Lightning. Lightning Facts. 2 nd Leading Cause of Weather Deaths in the United States. Kills more than Hurricanes and Tornadoes combined! Kills ~ 100 / Year Kills ~ 10% of those Struck. See how lightning works….

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Lightning

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  1. Lightning

  2. Lightning Facts 2nd Leading Cause of Weather Deaths in the United States • Kills more than Hurricanes and Tornadoes combined! • Kills ~ 100 / Year • Kills ~ 10% of those Struck

  3. See how lightning works… • http://environment.nationalgeographic.com/environment/natural-disasters/lightning-interactive/

  4. Cool You Tube Videos • http://www.youtube.com/watch?v=_X_7YRVGvtA&feature=related • http://www.youtube.com/watch?v=-bvmEYxEYiA&NR=1

  5. Facts about Lightning • A strike can average 100 million volts of electricity • Current of up to 100,000 amperes • Can generate 54,000 oF • Lightning strikes somewhere on the Earth every second • Kills 100 US residents per year

  6. Lightning Doesn’t Go Straight Down

  7. What Does This Mean? • Lightning appears jagged because it will travel the path of least resistance to the ground • Lightning can strike ground up to ten miles from a storm (Lightning out of the blue) • There is an average of 2-3 miles between strikes • So how can we tell how far away lightning has struck?

  8. “30 / 30 Rule” • If 30 Secs Or Less “Flash To Bang”- Seek Shelter • COMMON MISCONCEPTION • 1 second = 1 mile • ACTUALLY • 5 seconds = 1 mile • Wait 30 Min After Last Lightning, Before Leaving Shelter • May Seem Too Conservative--It’s NOT!

  9. Lightning Step Voltage 200,000 Volts Step Voltage Current flow thru earth generates voltage 8,000 volts across feet (Typical) 0 Volts far away KMS: 5/98

  10. Struck flag pole and dispersed

  11. Tree root system

  12. Indoor Lightning Safety • Avoid using telephone (remember the wires). • Avoid using water – sink, tub, etc. (plumbing) • Unplug appliances (remember the wires). • Inner rooms the best.

  13. Safe Locations #2 • Fully enclosed metal vehicles – car, bus, etc. • Close windows • Keep hands on lap It’s not the rubber tires that make a vehicle safe – it’s the metal enclosure (Faraday Cage)

  14. Safe Locations #3 • Remaining Outdoors • Stay away from rivers, lakes, or other bodies of water. Be aware of the potential for flooding in low-lying areas. • Stay away from natural lightning rods/tall structures such as: towers, tall trees, telephone poles/lines, tents with metal supports, etc. • Take shelter under a small tree among several large ones if possible. Stay at least six feet away from the tree trunk to minimize a side strike and step voltage. NEVER stand under an isolated tree.

  15. Lightning Safety Position (LSP) • Assume LSP. Crouch with feet as close together as possible. Have heels touch. Place hands over ears. -REMEMBER- DO NOT LIE FLAT ON THE GROUND

  16. 10 9 8 7 6 5 4 3 2 1 0 Lightning Certified Facility Lightning Protected Building Relative Lightning Protection Outdoors Lightning Safe Locations • Seek Proper Shelter • Buildings Much Better Than Vehicles • Large, Fully Enclosed, Substantially Built • Vehicles Offer Some Safety • No Place Outside Is Safe Near A Thunderstorm • Near  6 Miles

  17. Sources • Various internet sites • Fort Detrick Installation Safety Management Office

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