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LIGHTNING FACTS The average lightning stroke is 6 miles long.

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Presentation on theme: "LIGHTNING FACTS The average lightning stroke is 6 miles long."— Presentation transcript:

1 LIGHTNING FACTS The average lightning stroke is 6 miles long.
The average thunderstorm is 6-10 miles wide. The average thunderstorm travels at a rate of 25 mph.

2 Important You are in danger from lightning if you can hear thunder.
LIGHTNING FACTS Important You are in danger from lightning if you can hear thunder. Once the leading edge of a thunderstorm approaches to within 10 miles, you are at immediate risk due to the possibility of a lightning strike coming from the overhanging cloud. Lightning is the thunderstorm’s greatest killer. Lightning victims frequently are struck before or just after the occurrence of rain at their location. Many people apparently feel safe from lightning when not experiencing rain. A person who has been struck by lightning does not carry an electrical charge that can shock other people. If the victim is burned, provide first aid and call emergency medical assistance immediately. Look for burns where lightning entered and exited the body. If the strike cause’s the victim’s heart and breathing to stop give CPR until medical professionals arrive. Knowing how far away a storm is does not mean that you are in danger only when the storm is overhead. Lightning can strike you when there are clear skies above you.

3 When lightning hits the ground nearby, it is ‘grounded’ and I am safe.
LIGHTNING AND EARTH When lightning hits the ground nearby, it is ‘grounded’ and I am safe. Totally and absolutely FALSE. Despite the fact that we call the earth a “ground” it is very difficult to pump electricity into the ground. Most of the “earth” is a very good insulator. When lightning hits the ground, it spreads out along the surface and the first few inches of the ground in increasing circles of energy called “ground current.” If it contacts a fence or a water pipe or wire entering a house it can be transmitted for quite a distance and cause injury to persons near these paths. People, being bags of electrolytes, are better transmitters of electrical current than most of the ground. Many are injured by ground current effect each year as the lightning energy surges up the leg that is closer to the strike and down the one further away.

4 HOW MANY FLASHES ARE THERE
Cloud-to-ground More than one ground strike point Cloud flashes Over the continental 48 states, an average of 20 million cloud-to-ground flashes have been detected every year since the lightning detection network covered all of the continental United States in In addition, about half of all flashes have more than one ground strike point, so at least 30 million points on the ground are struck on the average each year in the United States. Besides cloud-to-ground flashes, there are roughly 5 to 10 times as many cloud flashes as there are to ground.

5 WHAT IS THUNDER Air Heated Rapid expansion/contraction Sound Waves
Strikes Close By Strikes Farther Away Duration Thunder is caused by the extreme heat associated with the lightning flash. In less than a second, the air is heated to 15,000 to 60,000 degrees F. When the air is heated to such a high temperature, it rapidly expands (“explodes”) and then contracts. It’s this rapid expansion/contraction of the air molecules which causes sound waves which we “hear” at thunder. When lightning strikes very close by, the sound will be a loud bang, crack, or snap. The duration of the thunder associated with a nearby lightning strike will be very short. Lightning which strikes father away will rumble for a longer period of time as the sound arrives at different times due to the length of the lightning flash (typically many miles long). Thunder can typically be heard up to 10 miles away. During heavy rain and wind this distance will be less but on quiet nights when the storm is many miles away thunder can be heard beyond 10 miles.

6 SAFETY AWARENESS Things you can do to avoid becoming a lightning static: Plan Ahead Group Activity Nearest Shelter Take Action Plan ahead! Make sure you get the weather forecast before going out into the open. For a group activity, designate someone to keep alert to the weather. Know how far a safe shelter is from your present location, and know how long it will take you or your group to get to the safe shelter. Take action early enough to avoid getting caught in the storm: if you hear thunder, see lightning or see thunderheads rapidly developing overhead, Take Action. It is important to remember that lightning does not just strike near the heavy rain area of thunderstorms. Lightning can strike any miles away from the rain area. Lightning striking up to 20 miles away from a thunderstorm cloud in Florida have been documented.

7 FLASH TO BANG The flash to bang method is used to estimate lightning from your location. Divide the number of seconds by five (5) to get the distance the lightning is away from you. Example: If you see lightning and it takes 10 seconds before you hear thunder, then the lightning is 2 miles away from you (10 divided by 5 =2 miles)

8 SPORTS Outdoor sport activities are one of the worst for lightning victims such as: Soccer Baseball Golf

9 LIGHTING SAFETY FOR OUTDOOR ATHLETIC EVENTS
Responsible person Suspension and resumption Unsafe shelter areas Lightning’s electric field A responsible person should be designated to monitor weather conditions. Weather should be observed 24 hours prior to athletic events. An inexpensive portable weather radio is recommended suspension and resumption of athletic activities should be planned in advance. Understanding of safe shelters is essential. Safe evacuation sites include: fully enclosed metal vehicles with windows up. Enclosed buildings. The low ground. Seek cover in clumps of bushes. Unsafe shelter areas include outdoor metallic objects like flag poles, fences, high mast light poles, metal bleachers, golf carts, gates, etc. AVOID trees. AVOID water. AVOID open fields. AVOID using the telephone. If you feel your hair standing on end, and /or hear “crackling noise” - you are in lightning’s electric field. Immediately remove metal objects (including baseball cap), place your feet together, crouch your head and crouch down with hands on knees. Wait a minimum of 30 minutes from the last nearby lightning strike before resuming activities.

10 WORK RELATED Construction work is rated as the number #1 job for lightning victims.

11 CONCLUSION


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