Florida gets more lightning strikes than any other
state, and its most recent victim was diver Stephen Wilson,
36, who died in July when a lightning strike hit his tank. Despite a severe thunderstorm warning being in effect,
Wilson went diving with three friends in a small boat near
Deerfield Beach, 40 miles north of Miami. Wilson had resurfaced
30 feet from the boat when the lightning bolt struck
his tank and knocked him unconscious. The other divers
struggled to get Wilson back into the boat and radioed for
help, but to no avail. He was pronounced dead from electrocution
minutes later.
While 75 percent of fatalities by lightning strikes in the
U.S. are in open fields or near trees, 12 percent take place
in or near the water, in boats and on docks. So potentially,
lightning is the biggest weather danger for divers.
Oceans rarely attract lightning because the surface water
does not heat up enough to cause the positive charge needed
for lightning to occur. Also, water is always the lowest object
around, compared to land’s higher elevations and warmer
temperatures. But the main problem for divers is that water
is a good conductor of electricity, therefore the current of a
lightning strike can be carried through water for significant
distances. The last jump of a forming lightning bolt is only
100 to 150 feet long, so lightning can strike water more than
150 feet from shore and even if you are considerably below
the surface, you can still get electrocuted. However, because
the surface of a lake isn’t covered with dead fish after it’s
struck suggests the current weakens in short distances.
But what precautions should a diver take while caught
in a storm? Are you safer in the water than in the boat? If
shore diving, should you stay in the water or go ashore?
When I took my basic certification course in the 70’s, we
were told to get out of the water in a lightning storm and,
better yet, didn’t dive if lightning threatened. Today, however,
diving courses are shorter than ever so the question of
what to do about lightning is often ignored. PADI’s Open
Water manual has no reference to lightning or storms.
Jed Livingston, vice president of training for NAUI, says
it’s an obscure risk so there’s no need to cover it in courses. “It might be in our First Aid book but it discusses how to
treat an electrical burn. We assume divers already learned
what to do a long time ago during their swimming class
in school.” Scuba Schools International leaves it up to the
instructors’ discretion, says training director Dennis Pulley. “Those who live in areas more affected by lightning are
more likely to discuss it with students than those who don’t.”
Lightning is likely to strike the highest thing around so
if you’re on the water during a storm, the boat and everyone
in it are prime targets. Diving underwater may not be an
option because lightning can be even more deadly when
its electricity flows through the waves. Underwater caves
can be an especially dangerous location. Two cave divers
were shocked by lightning while diving in Florida’s Ginnie
Springs Cave. They were 900 feet from the entrance when
lightning struck - - twice - - but they survived.
If the forecast is for thunderstorms, don’t go out on the water. Or you should return to shore before the storm
arrives. If you’re out diving and can see lightning or hear
thunder, you’re already at risk for a lightning strike. If the
clouds are coming your way, it’s time to head for shore. If
you see lightning, the flash-to-bang method can also help
determine whether lightning is moving closer (sound travels
about one mile every five seconds).
If you’re in a boat during a storm, David Sawatzky,
M.D., medical columnist for the Canadian magazine
DIVER, says it’s best to huddle in the middle of the boat as
far as possible from water, electrical equipment, radios and
anything metal. Lower the antenna and anything else sticking
up on the boat. If there is a lightning protection system
on the boat, don’t touch it.
The ultimate advice is to avoid diving or being in or
near water during a storm, and 30 minutes before and after
it hits. And don’t sit out on the dock or climb to the top of
the boat to enjoy the lightning show.