Lightning Stroke Length
Name: Lynn B.
Date: Thursday, September 12, 2002
Is it possible to measure the distance of lightening
through the sky? Like in miles or across the sky before it hits the ground
or anything else?
Technically it would be possible to measure the length of the path of a
lightning strike, if it were straight. A lightning bolt follows the path of
least resistance at the moment of initiation, and this is rarely a straight
line, and is unique for each strike. The length of path of the lightning
strike has little meteorological significance. Of more interest is the
polarity of the strike (whether positive or negative), and the
classification, or type of strike (cloud-to-ground, cloud-to-cloud, within
cloud, and cloud-to-air). Researchers are trying to determine if there is a
connection between those variables and whether a thunderstorm becomes severe
Wendell Bechtold, meteorologist
Forecaster, National Weather Service
Weather Forecast Office, St. Louis, MO
I do not know any specifics but it would seem reasonable that the length of
a lightning bolt could be measured. If the sky were photographed or
televised from several locations and were connected by clocks to measure
synchronous strikes it should be possible to triangulate the distance.
Doppler radar and/or conventional radar could also be used to determine the
altitude and position of cloud formations, coupled with photographic and/or
television monitoring should allow estimates of the lightning bolt length.
This would be very difficult, as lightning often takes a tortuous path,
following, quite literally, the path of least resistance - the ionized path
made by the initial leaders (which are usually not visible). The length
is affected by cloud base height, the height in the cloud of the charged area
from or to
which electrical charge goes or comes, absolute humidity of the air, elevation
of the land,
elevation of the point of land or object (tree, mountain top, radio tower,
and so on.
We often can estimate the vertical distance from point in the cloud to the
near the surface, but that is about the best that we can do.
David R. Cook
Atmospheric Research Section
Environmental Research Division
Argonne National Laboratory
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Update: June 2012