Lightning over Teton Valley

Lightning flashes across the sky as a thunderstorm approaches Teton Valley in Victor, Idaho.

From fishing, boating, hiking and climbing to softball, soccer and golf, summertime activities can frequently expose us to the dangers of lightning.

Knowing the dangers and what to do if caught outdoors in a thunderstorm, may help you avoid being zapped this summer.

Electrical casualties

Your standard household electrical outlet carries 120 volts of electricity. A single lightning bolt can generate up to 100 million volts of electricity for a microsecond.

The temperature of a lightning bolt during that split second can reach 54,000 degrees Fahrenheit, about five times hotter than the temperature on the sun.

The electrical energy and intense heat from lightning can hurt you in a number of ways, including the following:

• Direct strike: This rarely happens, but if you are unlucky enough to take a direct hit, it’s game over, right then and there.

• Conduction: Electrical energy travels through all metal objects, but also through graphite, carbon fiber and water. During electrical storms avoid direct contact with wire or chain-link fences, fishing poles, hiking poles, bicycles and boats. Think of sticking your finger in a light socket, multiplied by about 1 million.

• Side-flash: The heat and electrical current that emanates outward through the air from a nearby lightning strike can cause cardiac arrest, concussive injuries, severe burns and nerve damage.

• Ground currents: When lightning strikes the ground the electrical current is carried outward, radially, in all directions through the ground. If that current reaches where you are standing or sitting, it can travel through your body. Cardiac arrest, burns and nerve damage are all possible from ground current.

Direct hits and conduction account for about 20% of all lightning casualties. Side flash accounts for about 30%. Ground currents are the most common way people are injured or killed by lightning, accounting for 50% of the casualties, according to the National Weather Service.

Mountain Weather

Stand with your feet together to protect from ground current. Crouching helps reduce effects from side-flash. Or sit with legs crossed on a pad; while the pad keeps you dry, it does not insulate you from the electrical current.

Find shelter

The safest place to be during a thunderstorm is in a building or a car. A “building” means a four-walled structure with a foundation and grounded electrical and plumbing. A picnic shelter or large tent may keep you out of the rain, but your lightning exposure is the same as standing out in the open.

It is not the tires on your car that insulate you, but rather the metal frame and body of the car that dissipates the electrical energy around you. A motorcycle or bicycle do not offer this same “halo” of protection.

If there is not a building or car to retreat to, get to lower ground. Get off ridgetops or off the water if you can, and retreat to a grove of similar height trees to wait it out. Do not run for the biggest, lone tree to get out of the rain.

There is not much we can do to protect ourselves from a direct hit. Conduction is something we can protect ourselves from by not being in contact with any objects that can conduct electricity, including water.

Don’t huddle

Lightning that strikes nearby will generate intense heat and electricity, possibly resulting in side-flash injuries.

Think of a lightning bolt like a hand grenade. The standard U.S. Army grenade has a kill radius of around 25 feet and a casualty radius of roughly 50 feet. Of people are standing close together, that will result in more casualties.

When lightning is present, don’t huddle. Instead, spread out 25 to 50 feet apart. That way, if someone does go down after the explosion, others in the group can give aid.

Keep feet together

While ground current kills or injures the most people every year, it is perhaps the easiest to protect ourselves from. If you find yourself outside with no good place to hide when lightning is striking nearby, then just stand still with both feet together.

The current that travels through the ground will take the path of least resistance and can go up one leg, through your body and exit out the other leg. Keeping your feet together at all times can prevent that current from reaching your vital organs.

My hope is, by following this advice, you will have a safe and un-shocking summer.

Jim Woodmencey is the chief meteorologist at and has provided weather forecasting for the Jackson Hole and Teton range for over 25 years. Contact him via

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