Although the phrase “struck by lightning” is often used as a metaphor for when unlikely events actually come to pass, hikers should do everything they can to follow the rules of lightning safety.
It’s true that when you look at the numbers, getting hit by lightning remains a rare event. On average, 55 people are killed each year by lightning in the United States, according to the National Weather Service.
But there’s also little question that knowing how to protect yourself from lightning strikes is a key component of hiking safety.
Lightning is the third leading weather-related cause of death behind floods and tornadoes. Lightning also injures hundreds of other people—many of whom end up coping with lifelong medical problems.
And the weather service reports that the U.S. experiences 25 million incidents of cloud-to-ground lightning annually. According to the National Park Service, Grand Canyon National Park alone averages more than 26,000 lightning strikes per year.
Facts About Lightning
• The National Weather Service estimates your chances of getting hit by lightning in a given year are literally one-in-a-million. But over the course of a lifetime those odds drop to one-in-10,000.
• Lightning reaches temperatures of 50,000 degrees Fahrenheit—five times hotter than the sun.
• A bolt of lightning can reach five miles in length, then spread across a 60-foot area from its point of contact with the ground.
• Some forms of lightning can strike at great distances either in advance or behind the center of a thunderstorm—anywhere from five to 10 miles away. That means that people sometimes believe that they are at a safe distance when they are actually well-within range of lightning activity.
• Lightning is more common in spring and summer but can occur at any time of year and anywhere in the country.
Lightning and Hiking
The basic adage of lightning safety is that, “When thunder roars, go indoors.” For hikers, that rule is of little value. Quite simply there are no indoors to go to. And it’s not a good feeling.
Here’s a cautionary tale:
A few years ago, my wife and I headed out on a short hike in Grand Teton National Park. It was a quiet trail through a lodgepole pine forest and away from better-traveled routes.
I had noticed clouds moving in over the Tetons but didn't anticipate how fast the storm would build. About 45 minutes into the hike, we began to hear thunder. Before long, it was crackling through the forest and bouncing off the mountains with bright bursts of lightning getting closer all the time.
At that point, the one-in-a-million odds didn’t mean a whole lot. I was as scared as I’ve ever been on a hike and the whole thing could have been prevented by taking a few simple precautions.
I’ll spare you the specifics about which of the following guidelines I hadn’t followed. But I can guarantee that I’ll never be so cavalier about lightning safety again.
Check forecasts. Use Weather.Com or a reliable forecasting site to get predictions on conditions for the area where you will be hiking.
Hike earlier in the day. Thunderstorms are much more likely to develop during the afternoon, especially in mountainous areas. So if you’re planning a hike at higher elevations, try to be off of the trail before noon.
Stay vigilant. Look for cloud masses that begin to grow quickly and darken. Anvil-shaped clouds are a sign of potential thunderstorm activity. Watch the direction that clouds are moving and listen for any hints of approaching thunder. Increasing winds are also an indication of an approaching storm.
Follow the 30/30 Rule. Count the time between a lightning flash and the sound of thunder. Sound travels roughly one mile in five seconds. If the time between the lightning and thunder is less than 30 seconds, that means you’re well within the danger zone and need to find a safe spot.
Watch out for danger signs. If your hair begins to stand up or your skin tingles, those are both indicators of imminent lightning danger.
How to Protect Yourself
Avoid exposed areas. Ridgelines, open fields, lone trees or isolated groves, and tall, prominent outcroppings all increase your risk of being hit by lightning. But sheds, picnic shelters, and the mouths of caves are also dangerous choices.
Stay away from conductors of electricity. Avoid water (at least 100 yards away) and stay clear of metal objects, such as fences. If your day pack, trekking poles, or any other personal items have metal in them, move that gear 100 feet or more from where you will be.
Find a low protected area. You’ll want to locate a swale or low-lying spot but be careful not to take cover in an arroyo or creek bed where flash floods may get channeled. This is especially true during the Southwest’s monsoon season in such areas as Zion National Park.
Make yourself a small target. If you’re caught in a storm with lightning nearby, get into a crouching position with your head tucked and hands covering your ears.
Spread your group out. While you and your fellow hikers will feel a natural tendency to stay closely together, by remaining in a cluster, you create a bigger target.
Do not lie flat. Your goal is to minimize contact with the ground and the surface area of your body that's exposed to lightning.
Wait 30 minutes. To avoid lightning that may strike behind the storm, wait 30 minutes after you’ve heard the last thunder before leaving your safe area.
Treat victims. If lightning strikes anyone in your group, try to treat them as quickly as you can with proper first aid. But don’t put yourself or anyone else in your group at risk for more lightning injuries.