Lightning and Lightning Safety

Lightning Safety Awareness Week is June 22-28, 2014

In the United States, there are an estimated 25 million cloud-to-ground lightning flashes each year.  While lightning can be fascinating to watch, it is also extremely dangerous.  Each one of those 25 million flashes is a potential killer.  Based on data for the last 30 years (1981 to 2010), lightning has killed more than 1,600 people in the United States, an average of 55 people per year based on documented cases.  This is slightly less than the average of 56 deaths per year caused by tornadoes and more than the average of 39 from hurricanes.  However, because lightning usually claims only one or two victims at a time, and because lightning does not cause the mass destruction left in the wake of tornadoes or hurricanes, lightning generally receives much less attention than the more destructive storm-related killers.  Documented lightning injuries in the United States average about 300 per year; however, undocumented injuries caused by lightning are likely much higher.

During the past 45 years, lightning has killed about 61 people in Wisconsin.  During the same time period, lightning has injured more than 250 people in the state. Although no lightning fatalities have occurred in Wisconsin so far this year, at least 5 people have been killed by lightning nationwide. Damage to property from lightning has cost in the millions of dollars.

Cloud to Ground Lightning.

Cloud to Ground Lightning. Courtesy of Fir0002/Flagstaffotos

While many people think they are aware of the dangers of lightning, the vast majority are not.  This lack of understanding continues to be a significant problem in the United States.  Many people don’t act to protect their lives, their property, and the lives of others in a timely manner simply because they don’t understand all the dangers associated with thunderstorms and lightning.  This lack of knowledge can lead to very tragic consequences.

Education and awareness are keys to reducing the number of people struck by lightning.  People need to be aware of the activities and behavior that put them at a greater risk of being struck by lightning, and find out what they can do to reduce that risk.  Adults in charge of outdoor activities and events, particularly those that involve children, should have and follow a specific lightning safety plan so that they minimize the dangers of lightning for the participants and the spectators.

The greatest number of lightning deaths and injuries in the United States occurs during the summer months when the combination of lightning and outdoor summertime activities reaches a peak.  During the summer, people take advantage of the warm weather to enjoy a multitude of outdoor recreational activities.  Unfortunately, those outdoor recreational activities put them at greater risk of being struck by lightning.

“When you hear the thunder, chances are that you are within striking distance”

While virtually all people take some protective actions during the most dangerous part of thunderstorms, many leave themselves vulnerable to being struck by lightning as thunderstorms approach, depart, or are nearby.  Lightning can strike as much as10 miles or more away from the rain area of a thunderstorm;that’s about the distance that you can hear the thunder from the storm.  In some instances when a storm is ten miles away, it may even be difficult to tell that a storm is nearby.  However, IF YOU HEAR THE THUNDER, CHANCES ARE THAT YOU ARE WITHIN STRIKING DISTANCE OF THAT STORM.  Remember? when thunder roars, go indoors!

Inside homes, people must avoid activities which put their lives at risk from a possible lightning strike.  In particular,people should avoid contact with anything that conducts electricity and stay away from windows and doors.  People may also want to take certain actions WELL BEFORE the storm threatens, in order to protect property within their homes, such as sensitive electronic equipment.

Finally, in the unfortunate event that a person is struck by lightning, medical care may be needed immediately to save that person’s life.  Cardiac arrest and irregularities and nerve damage are common in cases where people are struck bylightning.  However, with proper treatment, including CPR if necessary, most victims survive a lightning strike, although the long-term effects on their lives and the lives of family members can be devastating.


Most lightning deaths occur during the summer months, and during the late afternoon and evening. These are the times when lightning is most likely to occur and when people are more likely to be caught out-of-doors.


What are some of the physical characteristics of lightning?

Answer: Lightning is a giant spark of electricity.  A typical lightning flash contains about 20,000 amps and several hundred million volts.  This compares to a standard household current of15 amps and about 115 volts.  Typically, a lightning flash is only 1 to 2 inches wide.  The step leader that initiates the lightning flash propagates downward from the cloud at a rate of about 200,000 miles per hour.  The return stroke (the current that cause the visible flash) moves upward at a speed of about 200,000,000 miles per hour (about 1/3 the speed of light).  In comparison, the sound of thunder travels at about 1,100 ft per second or about 750 miles per hour.

For additional information about lightning or lightning safety, visit NOAA’s Lightning Safety Awareness web site at:

This entry was posted in Weather Information and tagged , . Bookmark the permalink.

Comments are closed.