[TowerTalk] US Tower damaged by lightning

[Roger (K8RI)]

David Gilbert wrote:
> The last time this topic came up somebody made the distinction between 
> positive and negative lightning, so I did some Google searching on it 
> and found a ton of information on it ... most of it pretty scary.  
>   
Super Lightning, or Positive lightning was the thing of legend until the 
Astronauts noticing sprites extending into space above some 
thunderstorms caused enough interest to get research started.  
Apparently it is a bit more common in cooler weather and in the Northern 
states compared to the Southern states, but can occur any where and is 
just as unpredictable as regular lightning. Except one thing about it is 
predictable, its destructive power. There's still a lot unknown about it.


73

Roger (K8RI)
> There's even a Wikipedia page on it.  If I remember correctly, positive 
> lightning carries at least ten times the amount of energy as normal 
> lightning, part of it in the form of higher voltage but most of it in 
> the form of much higher current.  It pretty much fries everything in its 
> path and is truly wicked stuff.  It occurs pretty much randomly among 
> normal lightning at something approximating a 5% -10% rate (again from 
> my memory), and is known for being able to travel horizontally long 
> distances to reach ground.
>
> The Intellicast website includes a quasi real time map of lightning 
> strikes across the U.S., and they distinguish between negative and 
> positive strikes by using different colors (yellow for negative and red 
> for positive).  I check that site quite often during our summer 
> lightning season here in southern Arizona and the red dots show up more 
> often than any of us would probably like to see.
>
> http://www.intellicast.com/Storm/Severe/Lightning.aspx
>
> 73,
> Dave   AB7E
>
>
> On 4/28/2010 10:48 PM, Roger (K8RI) wrote:
>   
>> However there is lighting and then there is lightning. The power in
>> lighting bolts varies tremendously  by several orders of magnitude.
>> There there are the so called "super strikes" that are many times more
>> powerful than most lightning.  They are not only more powerful than
>> regular lightning, the main power is down instead of up and they are
>> usually associated with "sprites", which are seen well above the tops of
>> the clouds and extending into space.  These are the ones that blow holes
>> in big airplanes and are very destructive. A well laid out ground system
>> that would eliminate damage from garden variety lightning may lessen the
>> damage, but there is little that will protect from these.
>>     
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