give you the distance in miles from you to the lightning. For safety purposes,
a flash-bang time longer than 10-15 seconds is recommended. The "30-30"
rule is helpful...if less than 30 seconds from flash to thunder, one should
seek shelter, and not venture out until 30 minutes of silence (no thunder).
Although the flash and resulting thunder occur at essentially the same time, light travels
at 186,000 miles in a second, almost a million times the speed of sound. Sound travels at the
relatively snail pace of one-fifth of a mile in the same time. Thus the flash, if not obscured by
clouds, is seen before the thunder is heard. By counting the seconds between the flash and the
thunder and dividing by 5, an estimate of the distance to the strike (in miles) can be made.
Lightning detection equipment is available.
Seek shelter in a safe building and stay away from
windows telephones, other electrical or conductive
Remain or go inside a vehicle and avoid metal
Avoid open fields if possible.
Do not be the highest object.
Avoid contact with metal objects.
Avoid high terrain or bodies of water if able.
Avoid taking refuge under isolated trees or other
isolated tall objects.
Indications of imminent lightning:
May hear crackling noise or smell ozone
Hair may stand on end
Objects may take on a "blue" glow...St Elmo's
If any of the above: leave or crouch on the balls of
your feet with head down, don't touch ground with
hands (Lightning Safety Position).
In the Mountains:
mountaineering maxim: "on by noon, off by two"
move off ridges, summits; avoid drainages and shallow caves
avoid rappelling when lightning imminent
remove metal objects if strike imminent