Local news reports in Aberdeenshire concerning last nights storm had several
eyewitnesses describing trees "sparking and flashing as if covered with
fairy lights!".......was this imagination or is this a possible phenomena in
a strong electrical storm? I guess it is possible if they become charged
enough, I have certainly heard of mountaineers reporting ice-axes sparking
and crackling during storms and similar tales from fishermen seeing it
around boat masts.

JP


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St Elmo's fire? Wouldn't have thought that was likely from trees?
Maybe streamers? Never seen sparking trees before unless they have actually
been zapped.
Alex.

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Alex Stephens Jr
Wishaw, North Lanarkshire, Scotland
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"J.Poyner" wrote in message
...
Local news reports in Aberdeenshire concerning last nights storm had
several
eyewitnesses describing trees "sparking and flashing as if covered with
fairy lights!".......was this imagination or is this a possible phenomena
in
a strong electrical storm? I guess it is possible if they become charged
enough, I have certainly heard of mountaineers reporting ice-axes sparking
and crackling during storms and similar tales from fishermen seeing it
around boat masts.

JP


---
Outgoing mail is certified Virus Free. So if your computer explodes it's
not
my fault.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.735 / Virus Database: 489 - Release Date: 07/08/04

"Alex Stephens Jr" wrote in message
...


St Elmo's fire? Wouldn't have thought that was likely from trees?
Maybe streamers? Never seen sparking trees before unless they have
actually
been zapped.
Alex.

It had me thinking of streamers too but I wouldn't like to say for sure.
http://www.wrh.noaa.gov/Flagstaff/science/lightnin.htm

Jon.

"Jon O'Rourke" wrote in message


http://www.wrh.noaa.gov/Flagstaff/science/lightnin.htm

I think this bit has been superseded by some recent research that shows
electrons are dispersed far too quickly for electricity to build up
enough of a charge in one place in order to produce lightning.

"The formation of ice in a cloud appears to be very important in the
development of this charge separation and ultimately of lightning.

Inside a thunderstorm, these ice particles vary in size, from small ice
crystals to larger hailstones. Owing to the rising and sinking air
associated with thunderstorms, these particles collide frequently inside
the cloud. These collisions within the thunderstorm cause these
particles to build up electric charge.

Due to the different rates of
rising and falling within a thunderstorm, a separation of electrical
charge takes place. As the thunderstorm grows, intense electrical fields
can develop within it.

A large positive charge forms in the frozen upper
part of the cloud and two charge regions - a large, negatively charged
region and a smaller positively charged region - form in the lower
portion of the cloud.

The ground normally maintains a small negative
charge with respect to the atmosphere, but when a thunderstorm drifts
overhead, the negative charge at the cloud base induces a positive
charge on the ground below the storm. The positive ground current
follows the movement of the cloud like a shadow and concentrates on
elevated objects, such as trees, buildings, and higher portions of
terrain, in an attempt to establish a current to equalize the charges
between cloud base and ground.

Air, however is a good insulator, and the
electrical potential between cloud and ground must build up to levels of
tens to hundreds of millions of volts before the insulating properties
of the air break down and an ionized conductive channel is established
for the current to flow between the two charges.

If you have ever had
your hair stand on end while under a thunderstorm, you were in this
positive ground current, and could have become a lightning target."


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One of the former directors of the KNMI once told me that he saw St.
Elms fire over a wood many years ago.

Sytze Stel


"Jon O'Rourke" schreef in bericht
...

"Alex Stephens Jr" wrote in message
...


St Elmo's fire? Wouldn't have thought that was likely from trees?
Maybe streamers? Never seen sparking trees before unless they have
actually
been zapped.
Alex.

It had me thinking of streamers too but I wouldn't like to say for
sure.
http://www.wrh.noaa.gov/Flagstaff/science/lightnin.htm

Jon.

"Sytze Stel" wrote in message
. nl...
One of the former directors of the KNMI once told me that he saw St.
Elms fire over a wood many years ago.



Was that a joke or a typo?

Col
--
Bolton, Lancashire.
160m asl.
http://www.reddwarfer.btinternet.co.uk
http://www.reddwarfer.btinternet.co....rPictures.html

Col wrote in message ...
:
:"Sytze Stel" wrote in message
.nl...
: One of the former directors of the KNMI once told me that he saw St.
: Elms fire over a wood many years ago.
:
:Was that a joke or a typo?

In fact it may be neither. Remember that Sytze is Dutch.

In Dutch many saints are known by the Latin form of their names - e.g. St
Petrus and St Martinus for St Peter and St Martin.

St Elmo in Dutch is St Elmus. Sytze may have assumed - wrongly in this
case - that the English form of the name could be obtained simply by
removing the Dutch "us".

Colin Youngs
Brussels

"Colin Youngs" wrote in message


Sytze may have assumed - wrongly in this
case - that the English form of the name could be obtained simply by
removing the Dutch "us".

Doesn't work for us though does it.




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"Colin Youngs" schreef in bericht
...
Col wrote in message ...
:
:"Sytze Stel" wrote in message
.nl...
: One of the former directors of the KNMI once told me that he saw
St.
: Elms fire over a wood many years ago.
:
:Was that a joke or a typo?

In fact it may be neither. Remember that Sytze is Dutch.

In Dutch many saints are known by the Latin form of their names - e.g.
St
Petrus and St Martinus for St Peter and St Martin.

St Elmo in Dutch is St Elmus. Sytze may have assumed - wrongly in
this
case - that the English form of the name could be obtained simply by
removing the Dutch "us".

Colin Youngs
Brussels


Thank you, Colin. I should have consulted my dictionnary first.

Sytze Stel