The lightning safety community reminds you that there is little you can do to substantially reduce your risk if you are outside in a thunderstorm. The only completely safe action is to get inside a safe building or vehicle.
This week is Lighting Safety Week (June 22-28) and just how dangerous lighting can be. A lightning flash can travel horizontally many miles away from the thunderstorm and then strike the ground. These types of lightning flashes are called “Bolts from the Blue” because they seem to come out of a clear blue sky. While blue sky may exist overhead (or in part of the sky overhead) a thunderstorm is always located 5 to 10 miles (and sometimes even farther) away. Although these flashes are rare, they have caused fatalities.
Facts to keep in mind: 1) 3,696 deaths were recorded in the U.S. between 1959 and 2003 or cause cardiac arrest. Injuries range from severe burns and permanent brain damage to memory loss and personality change. About 10 percent of lightning-stroke victims are killed, and 70 percent suffer serious long-term effects. About 400 people survive lightning strokes in the U.S. each year.
If you can hear thunder,you are within 10 miles (16 kilometers) of a storm—and can be struck by lightning. Seek shelter and avoid situations in which you may be vulnerable.
• Use the 30-30 rule,when visibility is good and there is nothing obstructing your view of the thunderstorm. When you see lightning, count the time until you hear thunder. If that time is 30 seconds or less, the thunderstorm is within six miles (ten kilometers) of you and is dangerous. Seek shelter immediately.
The threat of lightning continues for a much longer period than most people realize. Wait at least 30 minutes after the last clap of thunder before leaving shelter. Don’t be fooled by sunshine or blue sky!
• Most lightning deaths and injuries in the United States occur during the summer months, when the combination of lightning and outdoor activitiesreaches a peak. People involved in activities such as boating, swimming, fishing, bicycling, golfing, jogging, walking, hiking, camping, or working outdoors all need to take the appropriate actions in a timely manner when thunderstorms approach.
• The Fourth of July is historically one of the most deadly timesof the year for lightning in the U.S.. In summer, especially on a holiday, more people are outside, on the beach, golf course, mountains, or ball fields. Outdoor jobs such as construction and agriculture, and outdoor chores such as lawn mowing or house painting are at their peak, putting people involved in danger.
Where organized sports activities take place, coaches, umpires, referees, or camp counselors must protect the safety of the participantsby stopping the activities sooner, so that the participants and spectators can get to a safe place before the lightning threat becomes significant.
• People on or in or near water are among those most at risk during thunderstorms. Swimming is particularly dangerous,as not only do swimmers protrude from the water, presenting a potential channel for electrical discharge, but also because water is a good conductor of electricity.
• Inside homes, people must also avoid activities which put their lives at risk from a possible lightning strike. As with the outdoor activities, these activities should be avoided before, during, and after storms.
In particular, people should stay away from windows and doors and avoid contact with anything that conducts electricity, including landline telephones.Most people hurt by lightning while inside their homes are talking on the telephone at the time.
• People may also want to take certain actions well before the storm to protect property within their homes, such as electronic equipment. Surge protectors do not protect against direct lightning strikes.Unplug equipment such as computers and televisions.
• If a person is struck by lightning, medical care may be needed immediately to save the person’s life. Cardiac arrest and irregularities, 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,although the long-term effects on their lives and the lives of family members can be devastating.
• A house or other substantial building offers the best protection from lightning. For a shelter to provide protection from lightning, it must contain a mechanism for conducting the electrical currentfrom the point of contact to the ground. These mechanisms may be on the outside of the structure, may be contained within the walls of the structure, or may be a combination of the two.
On the outside, lightning can travel along the outer shell of the building or may follow metal gutters and downspouts to the ground. Inside a structure, lightning can follow conductors such as the electrical wiring, plumbing, and telephone lines to the ground.
• Unless specifically designed to be lightning safe, small structures do little, if anything, to protectoccupants from lightning. Many small open shelters on athletic fields, on golf courses, in parks, at roadside picnic areas, in school yards, and elsewhere are designed to protect people from rain and sun, but not lightning.
A shelter that does not contain plumbing or wiring throughout or some other mechanism for grounding from the roof to ground is not safe. Small wooden, vinyl, or metal sheds offer little or no protection from lightning and should be avoided during thunderstorms.
• There are three main ways lightning enters homesand buildings: a direct strike, through wires or pipes that extend outside the structure and into the ground. Regardless of the method of entrance, once in a structure, the lightning can travel through the electrical, phone, plumbing, and radio or television reception systems. Lightning can also travel through any metal wires or bars in concrete walls or flooring.
• Phone use is the leading cause of indoor lightning injuriesin the United States. Lightning can travel long distances in both phone and electrical wires, particularly in rural areas.
Do not lie on the concrete floor of a garage as it likely contains a wire mesh. In general, basements are a safe place to go during thunderstorms. However, avoid contact with concrete walls, which may contain metal reinforcing bars.
Avoid washers and dryers, since they not only have contacts with the plumbing and electrical systems but also contain an electrical path to the outside through the dryer vent.
Avoid contact with electrical equipment or cords. If you plan to unplug any electronic equipment, do so well before the storm arrives.
Avoid contact with plumbing. Do not wash your hands, do not take a shower, do not wash dishes, and do not do laundry.
• Victims of lightning do not retain the chargeand are not “electrified.” It is safe to help them.
• Rubber shoes will not give you any meaningful protectionfrom lightning.
• Lightning can—and often does—strike in the same place twice.Tall buildings and monuments are frequently hit by lightning.
• A motor car with a metal top can offer you some protection—but keep your hands from the metal sides.
• An umbrella can increase your chances of being struckby lightning if it makes you the tallest object in the area.
• Always avoid being the highest object anywhere—or taking shelter near or under the highest object, including tall trees. Avoid being near a lightning rod or standing near metal objects such as a fence or underground pipes.
Most of the information on this page was adapted from the NOAA’s National Weather Service’s Lightning Safety Web site.