Lightning is more dangerous than you think
The following web story is a direct transcription from the National Weather Service regarding lightning awareness week. This is the fourth of a five part series on lightning safety which will run each day during New York's lightning safety awareness week. Today’s topic will focus on lightning safety indoors.
A house or other substantial building offers the best protection from lightning. To determine the safety provided by a structure, it is more important to consider what happens if the structure gets struck by lightning rather than whether it will be hit.
For shelters to provide protection from lightning, it must contain a mechanism to conduct the electrical current from the point of contact to the ground. These mechanisms may be on the outside of the structure, within the walls, or a combination of the two. On the outside, the lightning can travel along the outer shell of the building and may follow metal gutters or downspouts to the ground. Inside a structure, lightning can follow conductors such as electrical wiring, plumbing and telephone lines to the ground. Unless it is specifically designed to be lightning safe, small structures do little, if anything to protect occupants from lightning. Many small open shelters on athletic fields, golf courses, roadside picnic areas, and school yards are designed to protect people from rain and sun but not lightning. Shelters that do not contain plumbing or wiring throughout or some other mechanism for grounding from the roof to the ground are not safe. Small wooden, vinyl, or metal sheds provide no protection from lightning and should be avoided during thunderstorms.
There are three main ways lightning enters homes and buildings. They are: (1) By direct strike, (2) Through wires or pipes that extend outside the structure, or (3) Through the ground. Regardless of the method of entry once inside, lightning can travel through electrical and phone lines, 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 injuries in the United States. Lightning can travel long distances in both phone and electrical wires, particularly in rural areas. Stay away from windows and doors as these can provide a path for a direct strike to enter a home. Do not lie on the concrete floor of a garage as it is likely to contain a wire mesh. In general, a basement is a safe place to go during a thunderstorm. However, there are a few things to keep in mind. Avoid contact with concrete walls as they 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.
Lightning also caused significant damage to personal property last year. In addition to direct strikes, lightning generates electrical surges that can damage electronic equipment some distance from the electrical strike. To the extent possible, unplug any appliances or electrical equipment from all conductors well before the storm threatens your area. Don’t forget to disconnect televisions and radios from outdoor antennas. If you plan to be away from your home when storms are possible, be sure to unplug unneeded equipment before you leave.
Here is a quick summary of lightning safety tips inside the home:
1. Stay away from windows and doors.
2. Avoid contact with corded phones and with electrical equipment and cords.
3. If you plan to unplug any electrical equipment, do so well before the storm arrives.
4. Avoid contact with plumbing. This includes washing your hands, taking a shower or bath, washing dishes or doing laundry.
The topics for the remainder of the week are:
Friday: The medical aspects of lightning.
