Lightning

Frequently Asked Question

Lightning has fascinated and excited humans for as long as they have watched the skies. Meteorologists know the cloud conditions necessary to produce lightning, but cannot forecast the location or time of the next stroke of lightning from a storm. At any moment, there are as many as 1800 thunderstorms in progress somewhere on the Earth, and each is producing deadly lightning.

As the thunderstorm forms, it produces ice in the upper cloud. The formation of ice in a cloud is an important element in the development of lightning. Those storms that fail to produce large numbers of ice crystals may also fail to produce lightning. Strong rising and sinking motions within the cloud are important too, as they enhance collisions among cloud particles causing a separation of electrical charges. Positively charged ice crystals rise to the top of the thunderstorm and negatively charged ice particles and hailstones drop to the middle and lower parts of the storm.

As the differences in charges continue to increase, positive charges rise up taller objects such as trees, houses, and telephone poles. The charge can also move up you, causing your hair to stand on end! This is natures way final way of warning you that lightning can strike very soon near you.

The negatively charged area in the storm sends out a charge torward the ground called a step leader. It is invisible to the human eye and moves in steps torwards the ground. It takes less than a second for lightning to get close to the ground, and when it does it is attracted by all of the positively charged objects causing a channel to develop. You see the electrical transfer in this channel as lightning. There may be several repeated transfers of electricity within the channel. These are observed as flickering lightning.

Lightning Medical Impacts

Lightning usually claims only one or two victims at a time and usually does not cause the mass destruction left in the wake of tornadoes ot hurricanes. Lightning generally receives much less attention than any other weather hazards.

During a thunderstorm, each flash of cloud to ground lightning is a potential killer. However, lightning deaths can be prevented only if people are aware of the dangers and seek shelter in a building or a hard topped vehicle.

Lightning can strike as much as 10 miles away from the rain area in a thunderstorm. That is about the distance that you are able to hear the thunder from the storm. If you can hear the thunder from a storm, you are close enough to be struck by lightning.

Where organized sports activities are taking place, coaches, umpires, referees, or camp counselors must protect the safety of the participants and spectators by stopping the activities sooner so that participants and spectators can get to a safe place before the lightning threat becomes significant.

Lightning Facts
  • An average of 87 lightning fatalities are reported each year between 1959 and 1995.
  • About 10% of the people struck by lightning are killed... This leaves the other 90% with various types of injuries.
  • The primary cause of death from lighting is cardiac arrest.
  • Unlike high voltage electrical injuries with which massive internal tissue damage may occur, lightning seldom causes substantial burns.
  • Most lightning burns are caused by objects such as rainwater, sweat, metal coins, and necklaces being heated up and causing the burn.
  • Lightning tends to cause injury to the nervous system and may affect any or all parts of the nervous system.
  • If the brain is affected, the result is often difficulty with short term memory, coding new information, and accessing old information.
  • Most lightning injuries and deaths can be prevented with advance planning, being aware of the developing weather situation, and good common sense.
  • NOAA Weather Radio can help keep you informed with the latest thunderstorm information and safety reminders.
Lightning Safety

Being outdoors is the most dangerous place to be during a lightning storm. The National Weather Service advises that when you hear thunder or see lightning to quickly move indoors or into a hard topped vehicle and remain there until well after the storm has passed.

Any location is dangerous durning a lightning storm, however some areas are more dangerous than others. Some of the riskiest locations include:

  • Anywhere near the water:
    • Boating
    • Fishing
    • Swimming
    • Activities on the Beach
  • Areas near tall trees:
    • The Golf Course
    • Picnic Areas
    • Hiking Trails
    • Isolated tall trees pose the greatest danger!
  • High terrains such as hill tops and ridges
  • High places such as house roofs during construction
  • Open areas like fields

Dangerous situations can arise when big groups of people come together outdoors during a lightning storm. This includes baseball, football, soccer, and tennis games, as well as community fairs and outdoor festivals.

It is important that everyone know some outdoor and indoor safety rules.

Outdoor Safety Rules

Knowing outdoor safety rules can help save your life or that of loved ones.

When lightning approaches, get inside a completely enclosed building. Carports, open garages, storage sheds, metal sheds, and covered patios are not safe shelters.

If no enclosed building is available, get inside a hard-topped, all metal vehicle.

Get out of the water! Get off the beach and out of small boats and canoes. If caught in a boat, crouch down in the center of the boat away from metal hardware. Avoid standing in puddles of water, even if wearing rubber boots. Thunderstorm winds create large waves and turbulent water, so please wear a life jacket!

If you cannot reach shelter, avoid being the tallest object in the area. Do not take shelter under an isolated tree or the tallest trees in the area. If you are in the woods, find shelter under the shorter trees.

If only isolated trees are nearby, crouch on the balls of your feet. A rule of thumb to follow is to stay twice as far away from a tree as it is tall. Don't lie on the ground.

Avoid caves or overhangs. The ground current from lightning is very strong and can jump the Gap.

Avoid leaning against vehicles and get off bicycles and motorcycles.

Indoor Safety Rules

When lightning strikes a building, house or other structure, it follows metal conductors such a electrical wiring, plumbing, and telephone lines from the structure to the ground. When this process occurs, it usually leaves the inhabitants unharmed.

Once lightning enters the home it can surge through the electrical, phone, plumbing, and radio/television reception systems. It can also travel through any metal wires or bars in concrete walls or flooring as well as windows and doors. It is important to avoid these conductors during an electrical storm.

Phone use is the leading cause of lightning injuries within the home. Lightning can travel long distances in both phone and electrical wiring, especially in rural areas where other conductors are limited.

Basements should be used with caution during thunderstorms because they usually contain conductors. Avoid contact with washers and dryers since they not only have contacts with the plumbing and electrical systems, but also have an electrical path to the outside through the dryer vent. Concrete floors should also be avoided as they usually contain some form of reinforcement which can easily become electrified by a nearby lightning strike. Avoid bathing during a lightning storm as the household plumbing can carry a deadly current.

For more information about lightning, visit the NOAA Lightning Website.