Your family is picnicking in a rural park about a half hour from where you parked your car. A thunderstorm sneaks up on you. What do you do?
1. The risk of being struck by lightning in the US is small: one to two per million people per year. However, this adds up to more than 400 serious incidents (often involving permanent neurological injuries) and about 50 deaths. Children are at the same risk as adults. Factors slightly increasing the risk include being in Florida, Texas or Colorado; summertime; late afternoon; rural and mountainous terrains; and being in, on, or adjacent to a body of water. Florida is considered the “lightning capital” of the country.
2. Heed thunderstorm warnings. A “thunderstorm watch” means conditions are favorable for severe weather to develop in an area; a “warning” means severe weather has been reported in the area. While meteorologists can usually predict thunderstorm activity for an area, they cannot always pinpoint where a storm will pop up and the track it will take. This results in many false alarms and makes some people weary of warnings, often ignoring them, especially when they have long-standing plans for the day.
3. Recognize the signs of an approaching storm. The sound of thunder is proof positive that lightning is sufficiently close that it can strike you imminently. While most strikes are preceded by rapidly darkening skies, strong winds and heavy rain, they can occur when the sky is blue and rain is absent. Note that in some mountainous areas thunderstorms are especially common, weather reports may be less accurate, mountains may hide approaching storms and dampen the noise of thunderclaps, and shelter may not be readily available.
4. Don’t wait to see if the storm will pass. Lightning can strike when the time from the lightning flash to the thunder crash is less than 30 seconds. Most lightning strikes involving people occur in the first ten minutes of the storm. Investigations of lightning-related injuries show that many victims chose inappropriate shelter when better ones were available or were minutes away from appropriate ones.
5. No outdoor place is totally safe from lightning. Ideally, find shelter inside solid, non-concrete four-wall structures with a roof. Concrete often contains metal wires that can attract lightning. However, the presence of electrical and telephone wiring and plumbing improves safety; wires and plumbing conduct electricity into the ground. This makes small buildings without plumbing or electricity less safe. Enclosed cars, large caves and narrow valleys are also protective.
6. Most lightning victims are hit in open fields or under a lone tree or a tree that towers over other trees. Being under many short trees gives some protection. Avoid being around flagpoles, light poles, tents, bleachers, picnic shelters, baseball dugouts, ski lifts and porches. Never use a rocky overhang for shelter.
7. If caught in a storm, avoid being the highest point. Get off elevated areas such as hills, mountain ridges or peaks. Crouch low, with as little of your body touching the ground as possible. Do not lie down. Lightning causes electric currents along the top of the ground that can be deadly over 100 feet away. Separate family members to reduce the number of people at risk. Running may help reduce the threat from ground current as it limits the time both feet are on the ground at any one time. Get out of and away from bodies of water.
8. Don’t hold objects in your hands that may contain metal. Golf clubs, fishing rods, and umbrellas can attract electricity. Stay away from wire fences, clotheslines, metal pipes, rails and other metallic objects. Cellular phones are safe to use during a storm.
9. Know when the “all clear” takes effect. The last portion of a storm is almost as hazardous as the onset. Lightning can strike after the main storm has passed and the sky is blue and there is no rain. Wait at least 30 minutes following the last roar of thunder and flash of lightning before resuming activities.
10. Miscellaneous. Up-to-the minute apps report weather activity for virtually the entire globe. People who have been struck by lightning are not “electrified” and are safe to touch. Being in your own home is not 100% safe in a thunderstorm. Stay away from windows and do not use corded telephones. See http://www.weather.gov/iln/lightningsafetyweek for detailed information.