You’re several miles into a hike when the sky suddenly turns dark. Rain starts pouring, thunder rolls across the mountains, and lightning flashes nearby.
Then you see what looks like the perfect place to wait it out: a rock overhang or an open picnic shelter.
You get underneath it, you’re dry, and your hiking shoes have thick rubber soles.
It certainly feels safer.
But are you actually protected from lightning?
Unfortunately, not nearly as much as you might think.
The Rubber on Your Shoes Won’t Save You
One of the most common misconceptions about lightning is that rubber-soled shoes provide protection from an electrical strike.
They don’t.
Lightning involves an enormous amount of electrical energy. A fraction of an inch of rubber underneath a hiking boot isn’t enough insulation to protect you from it.
It’s also why the common explanation that you’re safe inside a car because of the rubber tires isn’t correct.
A hard-topped vehicle provides protection primarily because the metal structure can conduct electrical current around the occupants. The tires aren’t what make the vehicle safe.
The same principle applies to your hiking boots.
If lightning strikes nearby, the electricity doesn’t necessarily need to travel straight down through your body and through your shoes to hurt you.
It can reach you in several other ways.
You Don’t Have to Be Struck Directly
When most of us picture a lightning injury, we imagine a bolt coming directly out of the sky and hitting someone.
That can happen, but direct strikes aren’t the only danger.
A particularly important hazard for hikers is ground current.
When lightning hits the ground, a tree, or another object, some of that electrical energy can spread outward through the surrounding ground.
If you’re standing nearby, the current can enter through one part of your body and leave through another.
That’s one reason lying flat on the ground during a thunderstorm isn’t recommended.
There’s also the possibility of a side flash.
Lightning can strike a nearby object, and part of the electrical current can jump from that object to a person.
That becomes particularly important when we start talking about trees, cliffs, caves, and rock overhangs.
Why a Rock Overhang Isn’t a Lightning Shelter
Rock overhangs are common along mountain trails, and during heavy rain they can look incredibly inviting.
You’re underneath thousands of pounds of rock. You’re out of the rain. You’re no longer standing in an open area.
It seems like you should be protected.
But imagine lightning strikes the rock formation directly above you.
Electrical current can travel along wet surfaces and through portions of the rock toward the ground.
If you’re standing against the rock wall, sitting on the rock, or positioned near the entrance, you could become part of that electrical pathway.
Water running down a cliff can create another conductive path.
The National Weather Service specifically warns against using rocky overhangs and similar locations as lightning shelters.
So while an overhang might keep your backpack dry, it shouldn’t be mistaken for a lightning-safe structure.
What About a Cave?
A true cave is somewhat different from a shallow rock overhang, but that doesn’t mean every cave is automatically safe.
A cave entrance can be particularly problematic because current may travel across or around the opening.
A small recess in a cliff isn’t really a cave at all from a lightning-safety standpoint.
For a hiker caught in a storm, the important point is simple:
Don’t assume that getting underneath rock means you’ve escaped the lightning danger.
Picnic Shelters Feel Even Safer
A picnic shelter can feel even safer.
It has a roof. There are wooden posts. Maybe there are picnic tables underneath it.
It looks like a little building.
But there’s an important difference between a picnic pavilion and an enclosed building.
Most picnic shelters are open on several sides and don’t have the electrical and plumbing systems or substantial conductive structure associated with a lightning-safe building.
The National Weather Service does not consider open picnic shelters, pavilions, dugouts, sheds, or similar partially enclosed structures safe places during a thunderstorm.
They protect you from rain.
That doesn’t necessarily mean they protect you from lightning.
But Would I Leave a Picnic Shelter During Active Lightning?
This is where real-world hiking decisions become more complicated than simply saying, “Picnic shelters aren’t safe.”
Imagine lightning is already flashing around you.
You’re underneath a picnic shelter.
Your vehicle is two miles away.
Should you immediately run out of the shelter and into the storm?
Not necessarily.
You may not have a completely safe option at that point.
The National Weather Service emphasizes that no place outdoors is completely safe during a thunderstorm. When you’re deep in the backcountry, the objective becomes reducing your risk as much as reasonably possible.
That means considering the terrain around you rather than assuming one rule applies to every situation.
Leaving a picnic pavilion only to cross an exposed field or climb onto an exposed ridgeline could potentially put you in an even worse location.
Think in Terms of Relative Risk
For hikers, this may be the most useful way to understand lightning.
There is a difference between safe and safer.
A substantial enclosed building or hard-topped vehicle is the goal whenever one can reasonably be reached.
If those aren’t available, you’re choosing between imperfect options.
An exposed summit or ridgeline is particularly undesirable.
So is standing underneath the tallest isolated tree in the area.
A shallow rock overhang isn’t a proper lightning shelter.
An open picnic pavilion isn’t a proper lightning shelter either.
Lower terrain within a substantial forest containing relatively uniform trees is generally preferable to remaining exposed on high terrain.
The goal is to reduce your exposure until you can reach genuine shelter or the thunderstorm has safely passed.
Don’t Stand Under the Biggest Tree You Can Find
Another tempting shelter is a giant tree.
It’s raining hard, and the huge oak beside the trail has created a relatively dry spot underneath its canopy.
Don’t choose it simply because it’s dry.
A tall isolated tree can be more likely to receive a lightning strike than the surrounding terrain. A strike can then reach someone underneath through a side flash or ground current.
Being wet is uncomfortable.
Being wet isn’t the primary danger during a thunderstorm.
I’d rather get soaked in lower forested terrain among numerous similar-sized trees than stay dry directly beneath one towering tree.
Getting Wet Doesn’t Make You a Lightning Rod
Another misconception is worth clearing up.
Being soaked by rain doesn’t suddenly make you more likely to be struck by lightning.
Likewise, removing a metal necklace, dropping your trekking poles, or taking off a metal-framed backpack doesn’t magically make the lightning danger disappear.
Your location is far more important.
Are you standing on the highest point around?
Are you on an exposed ridge?
Are you underneath an isolated tall tree?
Are you beside a cliff?
Are you near water?
Or are you down in lower terrain surrounded by substantial forest?
Those are much more important questions.
What Should You Do When You’re Miles From the Trailhead?
This is the reality for people hiking places like Table Rock, Pinnacle Mountain, Caesars Head, Jones Gap, and the other trails throughout Upstate South Carolina.
Sometimes a thunderstorm develops despite a decent forecast.
You can’t magically transport yourself back to your vehicle.
If you hear thunder while you’re on an exposed summit, overlook, bald, or ridgeline, get off the exposed terrain and descend toward lower forested areas.
If you’re already deep within substantial forest, assess the terrain around you. Avoid isolated tall trees, exposed rocks, cliffs, streams, and other obvious hazards.
If an enclosed building or hard-topped vehicle is reasonably accessible, go there.
And remember that the storm isn’t necessarily over when the rain stops.
Lightning can occur outside the area of heavy rain. The National Weather Service recommends waiting 30 minutes after the last sound of thunder before considering the lightning threat over.
The Shelter That Keeps You Dry Isn’t Necessarily the Shelter That Keeps You Safe
That’s probably the biggest lesson.
When you’re hiking, and a thunderstorm suddenly arrives, your instincts tell you to find something with a roof.
A rock overhang has a roof.
A picnic pavilion has a roof.
A giant tree effectively has a roof.
All three can keep you relatively dry.
None should be confused with the protection offered by an enclosed substantial building or hard-topped vehicle.
And those thick rubber soles on your hiking boots don’t change that.
When you’re miles into the mountains with no genuine lightning-safe structure nearby, you may have to choose between several imperfect options. Your priority should be getting away from exposed high terrain and into the lowest-risk location reasonably available.
Because when lightning is involved, staying dry and staying safe aren’t necessarily the same thing.
Sources
National Weather Service, Lightning Safety:
https://www.weather.gov/safety/lightning
National Weather Service, Lightning Safety Outdoors:
https://www.weather.gov/safety/lightning-outdoors
National Weather Service, Lightning Myths:
https://www.weather.gov/safety/lightning-myths
National Park Service, Lightning Safety:
https://www.nps.gov/articles/lightning-safety.htm
