Incoming lightning bolt?
January 5, 2015 1:29 PM   Subscribe

Was I almost struck by lightning on a beach in Oregon? Long weird story.

Hi there, here's my very weird Christmas story.

My family and I traveled to the Oregon coast for the holiday week. Had a great time, thanks very much.

One day, we went walking along the beach at Driftwood State Park.

All four of us (me, wife, two boys) were in rain gear and rubber boots. With literally no one else on the beach, we let our dog run free. She is a high-energy dog, running everywhere and sticking her nose into everything.

From the parking lot, we walked straight to the beach and turned north. We got only 100 yards before turning back.

The day was cloudy, with only very small small patches of sky where it appeared it might clear. Right from the start, it was sprinkling rain, and I could see a large, dark cloud making its way to the beach.

The rain picked up. Beyond the surf zone and seemingly beneath the dark cloud, I could see a narrow patch of water with a strange sea state. It appeared as if there were larger waves beyond the surf zone and centered on this area. It made me wonder what a waterspout looks like before it's an actual funnel cloud.

Standing on wet sand near the water line, I looked down and saw a pretty mussel shell. I reached down to pick it up.

ZAP!

The mussel shell had shocked me with static electricity. A big shock. Two to three times more powerful than the typical static shock one typically encounters (e.g. by rubbing your feet on a carpet and touching a door knob).

What the fuck?

I touched it again. ZAP again. Same power.

I touched a large piece of driftwood. ZAP, a third time. Same power.

I called my wife over to the driftwood. ZAP, fourth shock, now to a second person. My wife said she felt it all the way up her arm.

I touched a third object, another piece of driftwood, not connected to anything. ZAP, fifth shock. Same power.

The rain had picked up even further, and now it felt like a little bit of hail mixed in.

Fuck this, I said. I'm not ignoring possible lightning warnings. We turned around and left. On the way out, I touched two more pieces of driftwood, and got two more shocks. But they were progressively weaker, as if I had moved farther away from the center of something.

Note that during this whole time, the dog -- a very furry Portuguese Water Dog -- which was touching everything in sight, didn't give any outward indication that anything was awry. No yelps, no jumps.

I did not hear thunder or see lightning anywhere.

After it was over, I researched lightning safety, and saw typical warnings such as hair standing up, metal objects buzzing, etc. Apart from what I described here, I didn't experience any of those things.

I also wondered, buried electrical cable? This doesn't make sense to me, though. Secluded beach in a state park, touching grounded pieces of driftwood and objects on the sand itself.

I also thought about the fact that I had rubber boots. But, I was soaking wet, standing on sand, and again, the dog didn't yelp or behave any differently than at any other time.

Was a lightning strike imminent? Or am I missing something else that is obvious?
posted by Cool Papa Bell to Grab Bag (6 answers total) 11 users marked this as a favorite
 
this happens a lot near water during lightning storms... what you felt was the precursor to a lightning strike... there is a big build up of static electricity on the ground when there are strikes in an area.

you were wise to leave.
posted by bobdow at 1:54 PM on January 5, 2015 [9 favorites]


This is really common in Florida, lightening capital of the world. Before a lightening strike, there's electrical discharge on the ground. If you feel it, time to get outta there.

Porties are the best, aren't they?
posted by Ruthless Bunny at 2:22 PM on January 5, 2015 [1 favorite]


I have a piggyback question (because this intrigues me): If it was electrical discharge prior to a lightning strike, how long was that preliminary state last? I sounds like this went on for minutes. Does lightning know where it's going to strike minutes in advance?
posted by mudpuppie at 4:21 PM on January 5, 2015 [1 favorite]


Note that during this whole time, the dog -- a very furry Portuguese Water Dog -- which was touching everything in sight, didn't give any outward indication that anything was awry. No yelps, no jumps.
...
I also thought about the fact that I had rubber boots. But, I was soaking wet, standing on sand, and again, the dog didn't yelp or behave any differently than at any other time.


I'd say the reason for this is that the charge on the underside of the clouds induced an opposite charge on the ground and on the dog who was fully in electrical contact with the ground, driving the like charges which would ordinarily make things pretty close to neutral entirely out of the frame to a region of the beach not directly under the cloud -- and those charges could be driven away like that because of the electrical conductivity of the seawater-saturated beach.

However, your insulating rubber boots prevented much of any charge from being conducted entirely out of you, so the most the cloud was able to do you was produce a charge separation within your body; but when you touched the shell or the driftwood, the separated charges with the same sign as the charges on the underside of the cloud suddenly had a pathway to get away from there, and you and your wife experienced that flow as a shock.

The dog did not experience any shocks because she always had the same charges as the beach itself.
posted by jamjam at 4:49 PM on January 5, 2015 [2 favorites]


Lightning strikes up, strangely enough.

A charge imbalance develops in the clouds, with a negative charge at altitude and a positive charge nearer the ground. When there's such a charge, physics says that static electricity on the ground will be attracted, until it reaches an equilibrium where the attraction of the positive clouds matches the repulsion of the electric charge on the ground which has already collected.

Then, if the charge in the clouds increases, more electrons will collect on the ground until a new equilbrium is achieved.

If the charge in the cloud is large enough, and can thus collect a large enough electric charge on the ground, then the voltage difference may be enough to permit an arc to overcome air resistance, and then there's a lightning strike. But it's not guaranteed that this will take place; the charge may never reach that threshold.

And eventually the charge imbalance in the cloud will dissipate, and then the charge accumulation on the ground will dissipate.

It's been said that "lightning never strikes the same place twice" but in fact a lightning bolt is a bunch of sequential arcs. The initial arc drains the local charge around the source point on the ground, and does so faster than the charge can be replenished from the surrounding area, so the arc ends rapidly (milliseconds). Then more charge rushes in, and it reaches the proper voltage again and you get a second arc. This is because soil is a terrible conductor.

This can happen twenty or thirty times in the course of a fraction of a second. Formation of the second and subsequent arcs is aided by the fact that the first arc created a plasma channel in the air, so it takes less voltage the second time (because plasma is a better conductor).
posted by Chocolate Pickle at 9:26 PM on January 5, 2015 [6 favorites]


Thanks, all! Good to know that I wasn't just jumping at shadows. All's well that end's well.
posted by Cool Papa Bell at 9:18 AM on January 9, 2015


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