Thunder and lightning

Our group paddles lots of mountain rivers. We sometimes find ourselves faced with a thunder storm popping up very quickly. Which is better, and why, on the water or the shore?

Thunder is just noise, won’t hurt you. Lightning is dangerous on the water, get off the water immediately. On the water you’re the highest object and most likely to get struck by lightning, unless you’re in the middle of the desert there are plenty of things higher on shore that tend to get hit first.

Bill H.

weather radio
Carry a weather radio, they are cheap.

Bill H.

Off the water and away from shore.

Thunder won’t hurt you
but where there’s thunder, there’s lightning.

The junction that
current flows through, as illustrated in schematics, is called a node. A node is represented as a point where lines of a circuit intersect. On the water you resemble a node and lightning may mistake you as such.

I think it depends on the surroundings
Being the lone “node” on the middle of a large lake is a totally different situation than being on a small creek in a 300ft canyon. If I’m way below those large trees on the bluff, it makes more sense for me to stay on the water than to get out and be standing right beside a 70 foot tree. A large undercut ledge might be a better option as it can serve as a nice temporary shelter to wait out the storm.

So my thought is to look around and quickly get to a spot where you aren’t the tallest thing and where you aren’t standing on shore next to the tallest thing(s).


Mostly true
except for the random factor. Lightning strikes where the charge differential forms. Frequently the node is a high object. I work on the prairie in an area second only to Florida for lightning strikes in the U.S. We have wind turbines and meterological towers sticking up everywhere to the height of 80 meters. Sometimes the lightning will pick out a street light pole or even the side of a hill, starting a grass fire. Under a rock overhang would be a pretty good shelter. I would rather take my chances off the water in any situation.

So if lightning stuck . . .
. . . the water nearby while you were paddling would you get a jolt (not the drink)?

No ledges!
We’ve always been advised in mountaineering safety that undercut ledges are NOT a safe place to be in electrical storms as currents from nearby strikes will tend to travel into those areas through the ground. There have been a number of accidents, and, I believe, fatalities, reported over the years in the Alpine Club’s annual accident reports due to that phenomenon. I was taught that when you are caught out on an exposed slope during an electrical storm, you should crouch with head down on top of a backpack, foam pad, dry wood or other insulating material.

Speaking of electrocution, I recently researched marine electrocutions as a weekly safety report where I work. Kayakers and canoeists should also be aware that the waters around marinas can be dangerous. Faulty grounding and amateur electrical connections on docked boats have resulted in people being electrocuted by touching craft or structures or even simply due to currents flowing in the water. I’ve become much more cautious about navigating around marinas since reading the data and seeing photos of the horrible wiring at such places.

NOAA and the weather channel are
somewhat exaggerating the risks of one getting struck by lightning. If we followed their recommendations, outside recreation as we know it would be almost over.

If caught out on the ocean, a lake, or a river during a storm that includes lightning, evaluate your OVERALL situation, including risks from wind and waves. For a group, it might make sense to spread out so that if one is struck by lightning, the others are OK and can assist.

But the fact is, very few paddlers are struck by lightning while on the water. You aren’t a likely target, just a possible one. Be cool, make sure you don’t run into other trouble while running away from lightning.

Seems possible

more data on avoiding ledges and caves
Here is the Lighting Institute’s information on safety with the warning about rock outcrops:

It’s true that golfers are statisically at greater risk than wilderness outdoor recreationalists of being struck by lightning.

Excellent information.
Now, when on a trail in our mountains, do I stay away from under ledges and get bopped on the head from baseball size hail? So many ways to die, so many trails to walk and waters to navigate. Its OK to die happy doing something you love.

Can’t visit that site, WARNING
the secruity software says that it attaches to something called sirlinksalot and can breach security features.

Ledges and caves are rarely options.
Golfers tend to go for the little wooden shelters on high ground, so their argyle socks don’t get soaked.

I used to go over to the golf course as a thunderstorm was receding, and wade in the pools on the fairways to find golf balls I could sell. Never got struck. None of the other kids did either.

g2d makes a good point
Just this winter, I realized an alarming trend amongst weather forecasters. “It’s too hot, too cold, too humid, too dry, too sunny or too cloudy to go outside today. Better to stay indoors and stay tuned to Channel X” Weather forecasters have becomed the dupes of the advertisers.

Sorry, it’s off the original topic, but I had to vent (it is pouring down rain here).

Hadn’t thought of the ad issue. On one
broadcast, they claimed about 100 lightning deaths the previous year, and then on another, they said about 50. How many viewers die from thrombosis caused by sitting in front of the tube for hours?

Willowleaf, I think we need to see some
specifics as to why lightning current would tend to travel to undercut ledges. What would the strike location be? What would cause selective current travel to the area of the ledge?

There are other reasons, including avoiding hypothermia, why one might choose not to crouch in the open. I bring up again the two deaths and one near death when three women in separate locations panicked because of many nearby lightning strikes. They gathered some gear and tried to make it to base camp. Two died of hypothermia before they reached their goal. If they had stayed in their tents (under the aluminum poles), they would have lived. The tents were never struck.

ground current
willowleaf is right, caves and undercut ledges are places to avoid in lightning storms. The reason being that lightning strikes generate significant ground current - the lighting strike doesn’t stop once it hits the ground, it travels (often quite far) to balance the positive/negative charge differential between the underside of the cloud and the surface of the earth. Caves and overhangs tend to collect these ground currents mostly because they have more exposed surface area - i.e. if you’re huddled into a cave, you have a large amount of your body’s surface area in direct contact with rock. If it’s a big overhang, and you’re standing or crouching underneath it, it’s not really a problem (unless a rock falls on your head); the key is minimizing surface area contact. I say all of this as a non-expert - but this is my understanding of multiple conversations on the matter.

I’ve had more experience dealing with lightning on mountains than on the water (though I did once watch a lightning strike hit the water about a mile away, while I was wading back to shore from a sail mooring, and felt the electric current zip through me - tingly).

On a lake or wide river, I’d get off. 1-you want to avoid the semblance of a node, and 2-you don’t want to be out on open water if the storm gets worse. I’d get off the beach, try to stay away from any big trees, and minimize surface area (don’t lean against a tree or lie down). Shoes should be the only things in contact with the ground.

On a smaller stream, I’d worry a lot less about lightning - you’re just not in a position to draw undo attention to yourself. But I’d probably still get off, and follow the above - it’s still friggin’ raining.

My 2 cents