direction between crests. Recognize that
high waves are moving fast toward you.
Never get parallel to waves in an inlet. By
taking a course that is easier on both you
and the boat, you may actually be able to
travel faster and get there sooner (and less
tired) than if you traveled the most direct
route.
LIGHTNING
Lightning is one of the most underrated
sever weather hazards, yet ranks as one of
the top weather killers in the United States.
According to NOAA, lightning strikes in
America kill about 58 people and injured
hundreds of others each year. Lightning
can occur anywhere there is a thunderstorm.
Boaters are encouraged to avoid boating
when storms are predicted. There is no
substitute for being in a safe place during
a storm. When planning to go boating,
HAVE A LIGHTNING SAFETY PLAN that
includes provision for seeking safe shelter
in the event of an approaching thunderstorm.
Stay tuned to the NOAA VHF radio
weather channel. Recognizing that lightning
tends to strike the taller objects in an
area, being at sea in any boat and especially
a tall-mast sail boat during a thunderstorm
is great risk.
Lightning is a rapid discharge of electric
energy in the atmosphere. The resulting
thunder is the result of a shock wave
created by the rapid heating and cooling
of the air in the lightning channel. When
the many atmospheric come together to
form huge differences between the negative
charge in the cloud and positive charge
on the ground become large, the negative
charge starts moving toward the ground.
As it moves, it creates a conductive path
toward the ground. When the negative
charge from the cloud makes a connection
with the positive charge on the ground,
current surges through the jagged path,
creating a visible flash of lightning.
Lightning strikes occur before, during
and after a storm has passed. If thunder is
heard, then the storm is close enough for a
lightning strike. Seek safe shelter immediately
and remain in shelter at least 30 minutes
after the last lightning.
132 Chapter Three
Figure 11-15. Running parallel
to waves
Figure 11-16. Lightning strike
Lightning Quick Facts
Lightning often strikes the same place
repeatedly if it is a tall, isolated object.
Most lightning victims are in open areas
or near a tree.
Lightning strikes the U.S. about 25 million
times each year.
Lightning can heat its path through the air
to five times hotter than the surface of
the sun.
Figure 11-17. Lightning quick facts
Figure 11-18. Thunder warning
261
262
263
264
/www.lightningsafety.noaa.gov