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LIGHTNING


Florida is the lightning capitol of the United States and experiences thunderstorms on nearly one-third of the days in a year. Its unique geography is a key reason why Florida earns this distinction, especially during the summer. The Gulf of Mexico, to the west, and the Atlantic Ocean, to the east, surround the state and help to keep a warm and moist environment in place. This environment combines with strong summer sunshine, which heats the ground and causes warm air to rise. This creates small frontal boundaries along the east and west coasts, called sea breezes. These sea breezes push inland through the afternoon and allow thunderstorms to develop along the boundary. These boundaries often collide over the Central Florida Peninsula and generate additional thunderstorms that could become large and severe. Because thunderstorm activity peaks in the summertime, when the most people are working outdoors or enjoying outdoor activities, Florida often leads the nation in injuries and fatalities from lightning.

What Causes Lightning?

Within the thunderstorm, there are updrafts, where the air rises, and downdrafts, where the air falls. As the air in the updraft lifts higher, the small water droplets in the air freeze into small ice crystals and pellets. The ice particles collide with each other as they remain suspended in the updraft, and this friction causes an electrical charge difference within the cloud. The negative charges settle near the base of the cloud. The positive charges lift to the top of the cloud, and into the anvil of the thunderstorm. As the thunderstorm moves over the ground with this charge difference, it causes the ground and the objects on it to become positively charged. When the difference between the charges becomes too large, an electrical current begins to move between the cloud and the ground.

The visible flash of lightning occurs when the currents connect and discharge the energy. The currents look for the fastest route to make the connection. This is why tall objects, such as buildings and trees, will tend to be struck over shorter objects in the same area.

The speed of light travels much faster and farther than the speed of sound. This is why you see the flash of lightning first, and then hear the thunder. This is also why you can sometimes see lightning in the distance, but never hear the thunder with it. This is usually called heat lightning. Because of the delay between them, you can determine how far away the flash of lightning is by counting the number of seconds between the flash and when you first hear the thunder. For every five seconds counted, the lightning is one mile away.

Lightning Dangers

All thunderstorms contain lightning, regardless of the severity of the storm. Lightning can strike a person, a tree, or an object either on the ground or in the air. Over the last 10 years, lightning has killed an average of 39 people each year across the United States. Florida averages 6 deaths and 39 injuries a year. Lightning has also averaged over $6 million in damages each year to property in Florida.

Most people that are struck by lightning are not killed, but suffer significant injuries such as burns to their skin and, in some cases, cardiac arrest. It is important to remember that after a person is struck, they do not continue to carry an electrical charge and emergency medical services, if necessary, should be immediately performed.

Lightning is also dangerous because it can strike more than 10 miles away from where it is raining. Due to different winds in place near the top of the storm, lightning generated from the top of the thunderstorm can be displaced more than 10 miles away from the storm base, where it is raining. It is these lightning strikes that seemingly come from the “clear blue sky”. These “Bolts from the Blue” can be more dangerous since, as it is not raining in the immediate area, they can catch people off-guard.

Lightning Safety

A darkening cloud building high into the sky is often the first sign that lightning may strike. It is important to be observant while outside to keep yourself safe. Once you see lightning or hear thunder, you should immediately go inside a house, building, or other enclosed structure. A covered but not enclosed area, such as a dugout or awning, does not offer you protection from lightning. Once you are indoors, do not use any corded electrical devices, avoid using plumbing, and stay away from doors and windows. The electrical current from lightning can travel inside through wires, cables, and pipes.

If you are caught outside when a thunderstorm approaches and cannot make it indoors quickly, avoid open areas, such as a golf course or sports field, as these are the most dangerous places to be. This is because lightning tends to strike the tallest object in the area, which, in an open area, would be you. This is also why it is dangerous to stand under a tree in a storm. When you can’t make it into an enclosed building, the next best option is to get into a vehicle with a hard-topped roof.

It is equally as dangerous to be caught on the open waters of a lake or the ocean when a thunderstorm is approaching. Try to get back to land and find a safe building or, if possible, a safe vehicle. If that is not possible, then go inside the boat’s cabin and stay away from metal and all electrical equipment.

The key to staying safe from a lightning strike is to review the weather forecast before you go outside, and then monitor the sky conditions, looking for darkening skies and listening for distant rumbles of thunder once you are outdoors.

The best lightning safety rule is this: If thunder roars, go indoors!

Lightning Safety Awareness Week is June 24-30, 2012

More information about lightning hazards and what you can do to protect yourself and others can be found at
http://www.lightningsafety.noaa.gov and http://www.floridadisaster.org/.

 

 


  • Lightning heats the air to 50,000 degrees Fahrenheit, which produces the shock wave that results in thunder.
  • Lightning often strikes outside of heavy rain and may occur as far as 10 miles away from any rainfall. The average length of cloud-to-ground lightning is from two to 10 miles.
  • You can tell how far away lightning is by counting the seconds between seeing the lightning flash and hearing thunder. For every five seconds you count, lightning is one mile away.
  • The steel frame of a hard-topped vehicle provides increased protection if you are not touching metal. Although you may be injured if lightning strikes your car, you are much safer inside a vehicle than outside.
  • Heat lightning is a term used to describe lightning from a thunderstorm too far away for the thunder to be heard. Although rare, lightning can still travel up to 25 miles from the storm and people should still be cautious of lightning dangers.
  • Avoid open high ground and isolated large trees.
  • Avoid water (swimming pools, lakes and rivers), beaches and boats.
  • Seek shelter inside a building or an automobile, but not a convertible or a golf cart.
  • Stay away from doors, windows, and metal objects such as pipes or faucets.
  • Stay off the telephone and away from electrical devices.
  • Use the 30-30 rule for outdoor activity.
  • Monitor your NOAA Weather Radio.
Use ‘The 30-30 RULE’ to determine the threat of lightning in your area.
  • 30 Seconds:
    Count the seconds between seeing lightning and hearing thunder. If this time is less than 30 seconds, lightning is still a potential threat. Seek shelter immediately.
  • 30 Minutes:
    After hearing the last thunder, wait 30 minutes before leaving shelter. Half of all lightning deaths occur after the storm passes. Stay in a safe area until you are sure the threat has passed.
If someone is struck by lightning, what should you do?

In the event that a person is struck by lightning, medical care may be needed immediately to save the person's life. Lightning victims do not carry an electrical charge and are safe to touch and help. Cardiac arrest is the immediate cause of death for those who die. Some deaths can be prevented if the victim receives the proper first aid immediately. With proper treatment, most victims survive a lightning strike.

  • Call 911. Provide directions and information about the lightning strike and victim(s).
  • Give first aid. Do not delay CPR if the person is unresponsive or not breathing.
  • If possible, move the victim to a safer place. Lightning can strike twice. Don’t become a victim.

Updated:

January 10, 2012 15:58