Lightning storms strike fear in many people, and with good reason. The average lightning bolt carries about 30,000 amps of charge, has 100 million volts of electric potential, and is about 50,000 degrees Fahrenheit. According to the National Weather Service, lightning routinely kills more people annually than tornadoes or hurricanes.
Lightning is unpredictable; it is hard to predict when and where it will strike and how it will behave when it does. In addition to the visible flash that travels through the air, the current associated with a lightning discharge travels along the ground. Although some victims are struck directly by the main lightning stroke, many victims are struck as the current moves in and along the ground.
If you can hear thunder, you are within 10 miles of a storm—and can be struck by lightning.
Most people do not realize that they can be struck by lightning even when the center of a thunderstorm is 10 miles away and there are blue skies overhead. If you can hear thunder, you are within 10 miles of a storm—and can be struck by lightning. Seek shelter and avoid situations in which you may be vulnerable.
Lightning can strike individuals in several ways:
- Direct Strike: Occurs to victims who are in open areas. Direct strikes are not as common as the other ways people are struck by lightning, but they are potentially the most deadly.
- Side Flash: Occurs when lightning strikes a taller object near the victim and a portion of the current jumps from the object to the person. Most often, side flash victims have taken shelter under a tree to avoid rain or hail.
- Ground Current: When lightning strikes a tree or other object, much of the energy travels outward from the strike in and along the ground surface. This is known as the ground current. Anyone outside near a lightning strike is potentially a victim of ground current. Because the ground current affects a much larger area than the other causes of lightning casualties, the ground current causes the most lightning deaths and injuries. Ground current also kills many farm animals.
- Conduction: Lightning can travel long distances in wires or other metal surfaces. Most indoor lightning casualties and some outdoor casualties are due to conduction. Whether inside or outside, anyone in contact with anything connected to metal wires, plumbing, or metal surfaces that extend outside is at risk. This includes anything that plugs into an electrical outlet, water faucets and showers, corded phones, and windows and doors.
- Streamers: Develop as a downward-moving lightning bolt approaches the ground. The bolt often splits, forming branch-like flashes. Streamers are ionized currents of air originating from the ground, which extend upwards to meet these descending lightning bolts. They usually appear to be disconnected from the main strike (see photo above).
When Thunder Roars, Go Indoors!
There is no safe place outside during a thunderstorm. If you can hear thunder, you are within striking distance. So, if you are outdoors, seek shelter! Look for shelter inside a home, large building or a hard-topped vehicle right away. Do not go under tall trees for shelter. Wait at least 30 minutes after the last thunder before leaving your shelter.
People on or in or near water are among those most at risk during thunderstorms. This includes those on boats or at the beach or near pools. Swimming is particularly dangerous.
If you feel your hair stand on end, that means lightning is about to strike.
If you feel your hair stand on end, that means lightning is about to strike. Squat low to the ground on the balls of your feet and place your hands over your ears and your head between your knees. Make yourself the smallest target possible and minimize your contact with the ground; but do not lie flat on the ground. This is a last resort when a building or hard-topped vehicle is not available.
Lightning can follow conductors such as electrical wiring, plumbing and telephone lines to the ground. So inside homes, people should also avoid certain activities which could potentially put them at risk from a possible lightning strike.
In particular, people should stay away from windows and doors and avoid contact with anything that conducts electricity. Stay off corded phones, computers and other electronic equipment that put you in direct contact with electricity or plumbing. Most people injured by lightning while inside their homes are talking on the telephone at the time. Avoid washing your hands, bathing, doing laundry or washing dishes.
You may also want to take certain actions well before the storm to protect property within their homes. Surge protectors do not protect against direct lightning strikes. Unplug appliances and other electrical items, like computers, and turn off air conditioners. If you are unable to unplug them, turn them off.
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