Is it Dangerous to Use a Cell Phone in a Thunderstorm?
Ronald L. Holle
Vaisala, Inc.

ightning is far more dangerous than most people
realize. It kills 50 to 75 people annually in the US and injures
between 500 and 750.
Lightning also is a lot more common than
most people realize. Every year in the US, between 25 and 30
million lightning strikes hit the ground. Around the world,
approximately 2,000 thunderstorms (where there’s thunder, there’s
lightning) are occurring at any given time, with as many as 100
lightning strikes every second. About two-thirds of all
thunderstorms in the US occur in June, July and August.
At least 95% of lightning deaths occur
outdoors. If you see lightning, get inside your home or a large
building immediately.
To learn more about
lightning, Bottom
Line/Personal talked to Ronald L.
Holle, a weather consultant and former meteorologist with the
National Severe Storms Laboratory...
Is it dangerous to talk on a phone
during a thunderstorm? Corded phones are extremely
dangerous during a storm. Home phone lines are protected with surge
devices, but these defenses can be overwhelmed should lightning hit
a nearby power pole. Someone dies every few years while talking on
a phone during a lightning strike.
Caution: Homes in isolated areas are
more vulnerable because they don’t share power poles with as many
neighbors. In areas with multiple homes, the electricity is more
likely to be “diluted” because it splits in different
directions.
Portable (cordless) and cell phones are safe
to use during a thunderstorm.
Should I unplug my computer and TV
during a storm? No,
not during
a storm. Electronic devices should be
unplugged before
a storm arrives. A few years ago, a man in Phoenix
unplugged a device at the precise moment when lightning struck. He
was thrown across the room.
Every year, the insurance industry pays out
about a third of a million dollars in claims for losses due to
lightning. Many of these losses involve electronics that are blown
out by power surges.
It’s a good idea to protect electronic
equipment -- stereos, TVs, computers, etc. -- with surge
protectors. Good-quality ones typically cost between $50 and $100.
Like the surge protection built into houses, however, they don’t
offer 100% protection. Unplugging devices before a storm is the
best approach.
Can I get electrocuted in the shower
or bath? There was a report a few years
ago of someone who was killed by lightning when taking a shower.
Faucets, knobs and other metal fixtures are natural conductors of
electricity. So is water. A lightning strike that hits your house
-- or even comes close -- could potentially carry enough
electricity indoors through these natural conductors to cause
injury or death.
How safe am I in a car during a
thunderstorm? A fully enclosed metal-topped
vehicle is generally safe. (A convertible with a vinyl or cloth top
is not safe.) The metal-topped vehicle may protect you for the same
reason that buildings do -- the lightning travels through the
framework and to the ground. Even if you happened to be touching a
metal component, such as a door handle, most of the electricity
would flow around (not through) you.
There have been cases in which a lightning
strike vaporized a car antenna and broke the car’s windows, but the
people inside were unharmed.
Some people think that it’s the rubber tires
that make a car safe. Not true. A few inches of rubber can’t
possibly “ground” a car.
Is it really that dangerous to be
under a tree during a thunderstorm? It’s one of the most dangerous
places you can be. Lightning tends to hit the tallest objects in an
area. Trees are a natural target, but the lightning doesn’t stop
there. Electricity always seeks the easiest path to the ground.
Since people conduct electricity better than trees, the lightning
may jump sideways (a “side flash”) if you’re within three to six
feet of the trunk.
Is it true that golfers often get
hit by lightning? Fewer than 5% of direct
lightning strikes have involved golfers. However, golfers do share
with other outdoor enthusiasts the two main risk factors for
lightning strikes -- they’re out in the open, and they’re often
higher than the surrounding terrain.
Water activities -- boating, swimming, etc.
-- also are risky. The current from lightning hitting water or a
boat travels across the surface of the water for tens of yards and
can be deadly within that distance. Check weather reports, and stay
off the water if there is a chance of a storm.
How can I tell if lightning is close
enough to be dangerous? A thunderstorm doesn’t have to
be overhead to be dangerous. When you see a lightning flash, count
the seconds until you hear thunder. If the interval between
lightning and thunder is 30 seconds or less, get inside a
substantial building or a metal-topped vehicle. Wait 30 minutes
after the last flash before going back outside.
Does lightning ever hit the same
place twice? It happens all the time. The
Empire State Building gets hit an average of 23 times a year.
Should I close house windows during
a thunderstorm? Most people do close windows,
if only to keep out the wind and rain. However, lightning is no
more likely to strike through an open window than a closed one.
Caution: Always close windows if
there’s a tree nearby. You also might want to close blinds or
curtains. A lightning strike can cause the bark to explode off the
trunk, and the bark can travel about 50 feet. People have been
killed by flying bark. A window might offer some protection.
Does it make sense to get a
lightning rod for my home? Several hundred thousand homes
and small businesses are hit by lightning each year in the US. But
because of grounded electrical and plumbing systems, electricity
from a lightning strike flows around you -- through walls, plumbing
and wiring -- and dissipates into the ground. (Small sheds, picnic
pavilions and the like are not safe from lightning.)
These days, lightning rods are usually used
to protect hospitals, schools, police stations and similar
structures. When lightning hits, a lightning rod and its attached
thick cable take the surge in current safely to the ground.
A lightning rod on your home is not
necessary, but it can offer some peace of mind. The rod is more
likely to take the hit than the roof or another part of the house.
Having the rod take the hit means that the massive current surge
has a preferred path to follow. Otherwise, the current rips through
the house and looks for something to carry it, usually the wiring
or plumbing. But if the current doesn’t find these paths very
quickly in a short distance, then fire and other damage can
occur.
A rod costs about $1,000 or more installed.
Installation must be done by a licensed professional who
specializes in lightning protection (check the yellow pages, or
search under “lightning rod installation” on the
Internet).