Lightning !!

[MountainDon]

(I originally started this in the Off Topics section, but then realized that it also had more general info of interest so I put it here instead.)

Lightning has always been an interesting phenomenon to me, but since this summers closest ever (to me) strike I've had increased interest. I note news stories of lightning strikes with keener curiosity.

The latest involved an elk hunter in a wall tent with an outfitter's type wood stove. This has a metal chimney pipe exiting the roof. There was a thunderstorm and the hunter in the tent was killed when lightning struck Witnesses say the pipe glowed.

Which brings me to lightning facts and safety. We're probably all aware that it's a poor idea to stand under a tall tree during a storm. But did you know that it's now recognized that laying flat on the ground is not the best solution when caught outdoors, away from appropriate shelter? The best position to take is a squat with your feet close together, your arms around your legs and your head ducked low. No umbrellas please.

If you got this far you might be interested in some other facts about lightning.

Golf shoes with metal spikes are great ground conductors. Lightning caused fatalities for golfers come right after fishermen.

A building with plumbing and electrical systems (and their grounding) is safer than a non-serviced building. Metal roofs are a bonus for an enclosed building.

Proper  lightning rods and grounding of a building helps with protection.

Blunt rounded end rods are shown to be best.
http://www.usatoday.com/weather/resources/basics/2000-05-15-lightn-rod-tests.htm
http://www.ee.nmt.edu/%7Elangmuir/

Lightning rods do not prevent lightning strikes. Lightning rods assume the building will be hit and provides a clear safe path for the discharge. This can help prevent damage to electrical equipment.

An enclosed building is safer than an open building (open or screened gazebo, porch, etc.)

A metal roofed vehicle is a safe place to take refuge. Not because of the rubber tires, but because of the metal shell. The car may be struck, but inside you will be safe. Does not apply to soft top convertibles (up or down) or to non-metal roofs.

The average lightning bolt carries about 125,000,000 volts of electricity and a current of up to 10000 amps.

Rubber soled shoes are of no help. Your soles would have to be about a mile thick to be effective insulators.

If in a group split up, remove backpacks and place 30 feet away.

Lightning detection systems in the United States monitor an average of 25 million strokes of lightning from clouds to ground per year.

Counting the interval from flash to thunder in seconds, then dividing that by 5 will give the distance to the strike in miles.

And much much more info at these links...
http://www.srh.weather.gov/srh/jetstream/lightning/lightning_safety.htm
http://usscouts.org/usscouts/safety/safe-lightning.asp
http://www.stormwise.com/striking.htm
http://www.strikealert.com/LightningFacts.htm
http://news.nationalgeographic.com/news/2004/06/0623_040623_lightningfacts.html
http://www.usatoday.com/weather/resources/basics/wlightning.htm

Lightning Protection links
http://www.lightningsafety.com/nlsi_lhm/lpts.html
http://www.mcdonaldlightning.com/aboutus.htm
http://www.elec-toolbox.com/usefulinfo/lightprot.htm
http://www.lightning.org/?page=home

Lightning Protection [highlight]PARTS[/highlight]
http://www.lightningrodparts.com/parts1.html

More info for the Techies
http://www.lightningsafety.com/nlsi_lhm.html

[JRR]

Often the "indirect" affect of lightning can be .... well, shocking!

A sudden rainstorm rolled in while I was riding my bike late one evening.  I took shelter under the intrance stoop at the closed local grocery/filling station.  With my feet on the concrete pad intranceway, I kept the bike upright by leaning on the handle bars and gas tank.

When lightning stuck the ground a hundred, or more, feet away the bike "ate me up".  Luckily no one could hear my scream.  I afterwards had slight bruises on my arms and legs from the muscle reflex that caused me to strike the bike.

I think that the metal of the bike had assumed the same electrical charge that all the surroundings had just before the lightning strike.  But I was a better path than the rubber tires when it was time to dissipate that charge.

Makes me think that some folks who are "struck by lightning" ... are not directly struckl.

[tjm73]

The average lightning bolt carries about 125,000,000 volts of electricity and a current of up to 10000 amps.

That's 1,250,000,000,000 Watts!!! What is that? It's 1.25 trillion watts.

Too bad we haven't figured out how to collect and harness even half the energy from just one lighting storm. Would sure help with some energy issues.

[MountainDon]

JRR, you're a lucky guy. 90% of people struck by lightning are only injured, sometimes severely. It doesn't have to be a direct strike.

One of the outdoor rules of thumb is called the 30/30 rule. When you see an oncoming storm you should seek shelter when the second count from flashes you see to the thunder you hear is less than 30. Then stay under shelter until 30 minutes after the last lightning/thunder. I think that may be overly cautious, but who's to say? Lightning can precede storms. Apparently lightning strikes can also occur during nuclear detonations. Probably the last thing to worry about then though.

tjm, that would need one heck of a charge controller wouldn't it.

[tjm73]

tjm, that would need one heck of a charge controller wouldn't it.

The average US household uses 10656 kWh/year according to the US gov't.

One single lightning strike of 1.25x10^12 Watts is equal to ~347222kWh

25 million lightning strikes = 3.1x10^19 kWh or enough power top run approximately 204 million average US homes per year. And that's if we collected only 25% of the lightning energy.

[peter_nap]

Too bad we haven't figured out how to collect and harness even half the energy from just one lighting storm. Would sure help with some energy issues.

I've been thinking about that myself. I need a dependable source of power and have noticed that every time I tell a hunting or fishing story, there's plenty of nearby lightening


Glad you weren't hurt. I have to believe that God watches us all considering all the close calls we have.

[glenn-k]

That's a very close call, JRR.

Some bikers aren't so lucky.  Don, I wasn't going to post this but you jolted me into it.

http://www.mysteriousuniverse.org/?p=1626

Ow.

[MountainDon]

Yeoouch!  Dang, another thing to worry about.