Lightning Safety 101: Lightning Rules
There are many "rules" that we teach our students about how to be lightning safe, however most of them are simply common sense:
- Don't be the tallest object in your surroundings.
- Stay away from the openings and walls of a cave during a thunderstorm.
- If possible, don't be at the lowest point of a hill or side of a mountain because not only will water collect there, but ground current will likely flow through the area.
- If in a car during a lightning storm, roll the windows up as the electricity will actually flow around the outside of the car. If the windows are open, electricity may also go through the vehicle.
- If you feel the hair on the back of your neck stand up for no apparent reason, hit the floor, as a lightning bolt may be imminent within 2-3 seconds!
Remember the 30/30 lightning safety rule!
The 30/30 Lightning Safety Rule
By counting the seconds between when you see a lightning bolt and when you hear the thunder, you can tell the distance of the lightning strike. For every five seconds that you count, the strike is roughly one mile away. Using this information, whenever a storm is 6 miles away (30 seconds count), assume the lightning stance and hold until the storm has passed another 6 miles away, or another 30 seconds count. A similar version of this rule is used by pools and golf courses in urban settings, however the second '30' may also refer to waiting "30 minutes" until the last thunder is heard or lightning is seen to resume activity in the pool or golf course.
Programming Note: There is some discussion that this rule may not be very 'exact', however for the purpose of basic risk management and use in the field, the 30/30 lightning safety rule is still considered to be effective enough to use in wilderness settings. The speed of light (186,000 miles per second) is a constant and doesn't change, the speed of sound may change depending upon a number of factors including terrain, atmospheric moisture, etc.
The Lightning Stance
The lightning stance should be observed anytime you are in the great outdoors and you are unable to get into an appropriate shelter quickly. The stance is a way of getting low to the ground and potentially avoiding a either a direct lightning strike or getting shocked from ground current (which is actually one of the most common methods of injury from a lightning strike).
The key to the stance is to place a metal-free insulated barrier between you and the ground and crouch low to the ground on top of the insulator, covering your ears as a nearby lightning strike can easily cause hearing damage due to the sudden exploding air and loud explosion noise.
The most important rule is to be aware of your surroundings and environment!! Know when storms may occur, have a shelter in mind that you can utilize and a route to get there. DO NOT HESITATE when you have detected lightning in your area!!! Seek shelter immediately! If you are responsible for others, ie: Coach, Scout Master, Referee, Group Event management. Ensure that everyone takes shelter ASAP. DO Not Hesitate a large number of the deaths occur while people are seeking shelter—minutes count!
Usage of a lightning detector can increase the time you have to respond to the threat as it will detect lightning strikes (Cloud to Ground) far beyond your hearing or line of sight (up to 40 Miles away). It will tell you if a storm is approaching). We recommend StrikeAlert as a low cost and effective tool that can be used to increase your awareness of your surroundings and increase the time you have to plan and then respond to the threat of lightning!
We carry one with us at each wilderness medicine course that we teach, because one can never be too safe when it comes to lightning safety! In fact, our protocol is that when lightning is within 6 miles of our course location, we cease all outdoor activity and remain indoors. No golfer, Hiker, coach, or Scout Leader should leave home without it during periods when storms are forecast!