...when the lighting strikes...

[DougPaul]

The rule of thumb is to get away a distance at least half the height of the tree ... or building

Actually, a properly grounded structure (eg a lightning rod, antenna tower, metal frame building) provides a zone of protection with a radius similar to its height by attracting lightning to itself. The good grounding does not protect the structure from being hit--it just dissipates the ground currents effectively.

WARNING--this zone of protection is not absolute, just a zone of reduced probability.

The problem with a tree is that it is not a good enough conductor (the bolt can hit the tree and jump to nearby objects--such as you) and that it may send the ground currents out on the surface.

Doug

 

[SAR-EMT40]

Lightning always follows the rules. There is a tendency for people to believe that lightning always hits the higher object. This just isn't so. Lightning, like all electricity follows the path of least resistance. Always, without exception. Spotting that path can sometimes be harder that one might imagine.

If you provide a better path to ground than the building or tree than it will be you that the lightning will use to get to ground or the lower potential. Its trying to get home. If you provide it an easier way to get there then it will use you.

Keith

 

[DougPaul]

Getting away from the highest point of land is good advice, but it doesn't necessarily mean you are safe. I have witnessed lightning hit the Charles River not far from lots of tall skyscrapers. I also saw a video of lightning striking the ground right next to a tall building. (I can't find the link at the moment.) I don't know why it didn't hit the building, but someone standing next to the building thinking "I'm safe here because the building is a better target" might have been dead wrong.

Lightning is like the 800 lb gorilla--it can do anything that it wants to...

Following the rules of thumb reduces your risk (risk = probability of a hit times the damage from the hit), but does not reduce the risk to zero. But pragmatically, there are plenty of other risks in life, so reducing the risk due to lightning sufficiently below the sum of all other risks is generally adequate.

It's still best to follow all of the precautions to minimize your risk and never underestimate the potential danger when you are near a thunder storm.

Hear! Hear!

Doug

 

[jjmcgo]

Adam Oates

John Carter, Ken Hammond and Darren Puppa led RPI to the NCAA title in 1985.

http://www.hockeydb.com/ihdb/stats/pdisplay.php3?pid=4052

 

[kerry13]

A lot of good information, thanks. What I didn't see mentioned was post storm risk. Once the rain stops the risk does not. Lightning strikes ahead and behind the storm. Most experts apply the 30/30 rule. The first 30 applies to the lightning and subsequent hearing of the associated thunder and equates to: you are at risk when the storm is within 6-7 miles, as has been stated. The second 30 recommends waiting 30 mins after the storm has passed before resuming outside activities. Assuming storm is traveling at 15-20 mph this time would permit the storm to get 7-10 miles away. This would be very applicable to those who take quick refuge below treeline or who are forced to hunker in the open. Too often the storm ends abrupty and sun pops out quickly, but don't assume it is safe.

 

[Tom Rankin]

A lot of good information, thanks. What I didn't see mentioned was post storm risk. Once the rain stops the risk does not. Lightning strikes ahead and behind the storm. Most experts apply the 30/30 rule. The first 30 applies to the lightning and subsequent hearing of the associated thunder and equates to: you are at risk when the storm is within 6-7 miles, as has been stated. The second 30 recommends waiting 30 mins after the storm has passed before resuming outside activities. Assuming storm is traveling at 15-20 mph this time would permit the storm to get 7-10 miles away. This would be very applicable to those who take quick refuge below treeline or who are forced to hunker in the open. Too often the storm ends abrupty and sun pops out quickly, but don't assume it is safe.

In NY State, this practice is mandatory for outdoor High School sports. The kids are always antsy to get going again, but I'm sure the rule is there because someone was injured or killed, (and sued!), while playing sports just after a storm passed.

 

[DougPaul]

Too often the storm ends abrupty and sun pops out quickly, but don't assume it is safe.

LIghtning risk is not an on-or-off feature--it is alwas a matter of degree.

Lighting can come out of a clear sky with no warnings or nearby storm, so the risk is never zero. (The risk can, however, be extremely low...)

The risk is higher near a thunderstorm than when none is nearby, so being sheltered whenever one is nearby (both before and after) is a good strategy for reducing one's risk.

Doug

 

[jjmcgo]

The National Lightning Safety Institute (???) and the U.S. Golf Association teamed in a public-safety effort that I believe also included the Professional Golfers Association.
This link is from that effort:
http://www.lightningsafety.com/nlsi_pls/golfsafetyrecommend.html
Basically, the USGA permits any golfer to leave the course if he sees evidence of lightning. I believe the PGA honors this practice, as well. As one of the top golfers, Tom Watson usually is the first to leave the course so that others don't have to take the wrath of tournament officials.
It's not just the golfers who have to be removed from tournament courses, often there's up to 30,000 people that need to be moved to shelter, usually their own cars or buses.
The NLSI general recommendation is that you seek shelter if the storm is within six miles.
Lee Trevino and two playing partners were lightning victims during a 1970s tournament. After months of pain, Trevino had then-radical spinal surgery that allowed him to return but he lived a life of pain for a long time. The other two eventually had that surgery and never returned to pro golf.
Trevino said it dries out your spine, especially the discs.
The PGA will not resume play until 30 minutes has passed since the last observed flash.