By Dev K. Mishra, M.D., President, Sideline Sports Doc
The end of summer and early fall are some of the busiest times of the year for outdoor sports participation, and unfortunately this is also the time of year with the highest number of cloud-to-ground lightning strikes. According to data from the National Oceanic and Atmospheric Administration there are about 20 million cloud-to-ground lightning flashes each year. The highest number occurs in southeast Florida and decreases towards the western United States. In the chart at the right, the red areas indicate a high concentration of lightning strikes and the grey areas the least.
Lightning represents a significant risk to outdoor athletes. Metal objects such as golf clubs, aluminum baseball bats, and bicycles will all attract lightning. Lightning-related deaths are the third most common among weather- related deaths and account for between 50 and 300 deaths per year in the United States.
The best way to stay safe is incredibly simple: don’t be out playing if lightning is suspected. The National Athletic Trainers Association has issued a series of published recommendations that are well worth following:
- Absolutely no practice or games outdoors during active lightning storms.
- The “30-30 rule” is a useful guide to direct suspension and resumption of play during lightning activity:
- Since sound travels around a mile in five seconds at the Earth’s surface, if you see lightning and hear thunder five second later the lightning is about a mile away.Play should be halted whenever the time lightning is seen to the time thunder is heard is less than 30 seconds. At this “flash-to-bang time,” lightning is within six miles.
- Play should not resume until at least 30 minutes after the last sound of thunder or flash of lightning.
- Sometimes it’s hard to tell if the thunder you hear comes from the exact lightning flash you saw, which can make the distance estimate inaccurate. Be sensible: just don’t play in a thunderstorm.
- If you’re caught in a thunderstorm try to get indoors in a building. Buildings with electric and telephone wiring and plumbing are ideal because this can be a form of “grounding”, carrying the electrical current away. If there’s no building available, a hard-topped automobile with the windows closed is the next best option. Try not to touch metal in the car.
- Avoid contact with the tallest object in an open field (like a tall tree) or any body of water. The safest position to assume is a crouched position with the feet close together and weight entirely on the balls of the feet.
If you are running a team or league it’s best to have a clear policy in place at the start of the season for a lightning safety protocol, identifying safe locations, and guidelines for resuming play.
For further reading and guidance please consult the original reference for this article: Walsh KM, Bennett B, Cooper MA, Holle RL, Kithil R, Lopez RE: National Athletic Trainers’ Association Position Statement: Lightning safety for athletics and recreation. J Athletic Training 2000;35:471-477.