I sometimes hear about a person who was walking in a park, or other forested area, and gets hit by lightening during a thunderstorm. I’m not talking about someone on a golf course swinging a metal golf club, just a person wearing normal clothing and walking around. I usually rack this up to being in the wrong place at the wrong time, but I wonder if there’s something more to it than that.
If I’m hiking in a forested area, and a thunderstorm rolls in, I try to find a sheltered area under tall trees where I can stay relatively dry, and where I assumed the trees would take any lightening strikes instead of me, but it seems people get struck by lightening even where there are tall trees nearby.
So does huddling under trees during a lightening storm protect you, or is this faulty logic, and if getting under trees isn’t a good strategy, what is, assuming there are no buildings or bridges nearby to hide under?
Yes, it’s faulty logic. It’s essentially widely accepted lightning safety that it’s very dangerous to take shelter under trees in a thunderstorm link (you can find hundreds more off google.)
Lightning will take the path of least resistance, and that means it will often strike trees preferentially. But a human is actually a less resistant path than the tree, with its wood/sap vs our bodies which are full of saltwater essentially. So the lightning which initially was attracted to the tall tree, can very easily jump from the tree to your body which is a less resistant path than continuing on down the tree.
Current can also spread out from the tree, through the root system and into anyone standing on the roots etc. Lightning can strike the ground and you can be affected by the current some feet away. There are many instances of cattle huddling under a tree for shelter in a thunderstorm, the tree gets struck by lightning, and the farmer now has a bunch of dead cows.
a lightning bolt has a lot of energy to get rid of. it will split into a number of paths and because of the high voltage these paths will jump from thing to thing.
so some of a lightning bolt might go into a tree. on its way to the ground some of that lightning bolt might jump out of the tree and go through you to the ground.
if you are out in the open the best is to squat down with your feet together. having your body spread out or you feet touching the ground at two different spots is how greater damage might likely happen if you were struck.
Hiding under a tree is one of the worst things you can do. According to the NWS, 16 people have been killed by lightning so far this year. Two of them were near or under trees. In 2013, five people (out of 23 total lightning fatalities) were killed under trees. In 2012, 10 out of 28 fatalities were near or under trees.
Trees are bad for a bunch of reasons. First of all, lightning is many millions of volts at a few hundred thousand amps. If only a tiny fraction of that bolt splits off and goes through you, it is still plenty of electricity to kill you. To put it in perspective, your typical electric chair is a couple of thousand volts and only a few amps.
Trees are also bad because the huge amount of energy in a lightning bolt can instantly boil the sap, and the sudden pressure can cause the tree to literally explode. Not only can you be injured by flying tree fragments, but limbs or even the trunk can come apart and huge pieces of tree can fall on you.
Here’s what the NWS has to say with respect to lightning safety:
at this date, 4 of the 19 killed this year in the USA, were under trees.
as mentioned you can get some of the bolt as it leaves the tree or get some electricity into your body as it flows along the ground surface (this is very common).
I’ll add a couple of anecdotes to what has already been said.
Some years ago a group of local golfers were playing when a thunderstorm started.
They sheltered under a tree. Lightening struck the three and one man was killed, as he was leaning against the trunk. The others were hurt but survived.
A young man who worked at the Best Buy where I got my first computer was on a school trip to Colorado. They were on Pike’s Peak, but there was no storm. Seemingly from out of the blue lightening struck and killed him.
It can happen to someone just walking, and stay out from under the trees during a storm!
Lightning can strike as far as 10 miles away from a storm, but the distance to horizon is around 3 miles. They just couldn’t see the storm I expect, it was too far away.