Capital Area Chapter Blog

American Red Cross

2011 National Lightning Safety Awareness Week: The Science of Lightning


Lightning is a serious danger. Summer is the peak season for this deadly weather phenomenon, with Florida being the lightning capital of North America with an average of 1.4 million cloud-to-ground lightning strikes each year and typically leads the nation in lightning deaths and injuries with an average of 9 deaths and 60 injuries directly due to lightning each year. Learning about lightning and its dangers as well as safety measures can greatly reduce your risk from being affected by lightning.

The sicence of lightning:

Each spark of lightning can reach over 5 miles in length, soar to temperatures up to 50000 degrees Fahrenheit and contain up to 100 million electrical volts.
At any given moment, there are 1,800 thunderstorms in progress somewhere on the Earth. This amounts to 16 million storms each year! Scientists that study lightning have a better understanding today of the process that produces lightning, but there is still more to learn. We know the cloud conditions needed to produce lightning, but cannot forecast the location or time of the next stroke of lightning.

Lightning has been seen in volcanic eruptions, extremely intense forest fires, heavy snow storms and in large hurricanes, but is most often seen in thunderstorms. A thunderstorm needs 3 components in order to for. They are: moisture, instability, and a source of lift (such as a cold front or the sea breeze boundary).


Ice in a cloud seems to be a key element in the development of lightning. Storms that fail to produce quantities of ice may also fail to produce lightning. In a storm, the ice particles vary in size from small ice crystals to larger hailstones, but the rising and sinking motions within the storm cause numerous collisions between the numerous ice particles, causing the electrical charges within the particles to separate. 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.

At the same time, the negatively charged bottom of the storm attracts a pool of positively charged particles along the ground. As the differences in charges increase, positively charged particles rise up taller objects such as trees, houses, buildings, and telephone poles. The negatively charged area in the storms will send out a charge toward the ground called a stepped leader. It is virtually invisible to the human eye and moves rapidly toward the ground. When it gets close to the ground, it is attracted by all the positively charged objects and a channel develops. You see the electrical transfer in this channel as lightning.

The lightning channel heats rapidly to 50,000 degrees. The rapid expansion of heated air causes the thunder you hear. Since light travels faster than sound in the atmosphere, the sound of thunder will be heard after the lightning is seen.

Sometimes lightning originates in the cirrus anvil at the top of the thunderstorm. Lightning from this area is called positive lightning. This type of lightning is particularly dangerous for several reasons. It frequently strikes away from the rain core, either ahead of behind the thunderstorm. It can strike as far as 10 miles from the storm, in areas that most people do not consider to be a lightning risk area. Positive lightning usually carries a high electrical current which increases the lightning fatality risk to an individual.

To minimize the risk of being affected by lightning:
Watch for Developing Thunderstorms.
If you can hear thunder, you are within striking distance. Seek safe shelter immediately
Minimize the Risk of Being Struck: People must stop activities at the first roar of thunder to ensure everyone time to get a large building or enclosed vehicle. Leaders of outdoors events should have a written plan that all staff are aware of and enforce.
Things to Avoid: Stay off corded phones, computers and other electrical equipment that put you in direct contact with electricity. Stay away from pools, tubs, showers and other plumbing. Buy surge suppressors for key equipment. When inside, wait 30 minutes after last strike, before going out again.
Helping a Lightning Strike Victim: If a person is struck by lightning, call 911 and get medical care immediately. Cardiac arrest, burns, and nerve damage are common in cases where people are struck by lightning. However, with proper treatment, including CPR if necessary, most victims survive a lightning strike. You are in no danger helping a lightning victim. The charge will not affect you.

We will talk about the indoor and outdoor safety with lightning on Wednesday and Thursday. Don’t miss our upcoming articles for more information about lightning safety! :)

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This entry was posted on June 21, 2011 by in Preparedness.

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