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THUNDERSTORM SAFETY
Some thunderstorms can be seen approaching,
while others hit without warning. It is important to learn and recognize the danger signs
and to plan ahead.
WHAT IS A THUNDERSTORM?
A thunderstorm is a storm containing
lightning caused by un- stable atmospheric conditions. When cold upper air sinks and warm,
moist air rises, storm clouds or "thunderheads" develop. Thunderstorms may occur
singly, in clusters, or in lines. Thus, it is possible for several thunderstorms to affect
one location in the course of a few hours. Some of the most severe weather occurs when a
single thunderstorm affects one location for an extended period of time.
Severe thunderstorms can bring heavy rains
(which can cause flash flooding), strong winds, hail, lightning, and tornadoes.
In a severe thunderstorm, get inside a sturdy building and stay tuned to a
battery-operated radio for weather information.
WHAT IS LIGHTNING?
Lightning is an electrical discharge that
results from the buildup of static electricity between clouds and the ground. It always
accompanies a thunderstorm. When the buildup is strong enough to overcome the insulating
effect of the air, lightning appears as a "bolt". This flash of light can remain
within the clouds, occur between clouds, or strike toward the ground several miles from
the parent cloud.
Lightning is a major threat during a
thunderstorm. In the United States, between 75 and 100 Americans are hit and killed each
year by lightning. If you are caught outdoors, avoid natural lightning rods such as tall,
isolated trees in an open area and metal objects such as wire fences, golf clubs, and
metal tools.
| It is a myth that lightning never strikes twice in the
same place. In fact, lightning has favorite sites that it will strike several times in the
course of one storm. While thunderstorms and lightning can be found throughout the United
States, they are most likely to occur in the central and southern states. The state with
the highest number of thunderstorms is Florida |
B E F O R E
Learn the thunderstorm danger signs. Dark,
towering, or threatening clouds Distant lightning and thunder
Have emergency supplies on hand. Check for
hazards in the yard. Dead or rotting trees and branches can fall during a severe
thunderstorm and cause injury or damage.
Secure outdoor objects such as lawn
furniture that could blow away or cause damage or injury. Take light objects inside.
Shutter windows securely and brace outside doors. Turn on the battery operated radio or
television to get the latest storm information.
A WATCH OR A WARNING
Know the difference between a "severe thunderstorm watch" and
a "severe thunderstorms warning".
A severe thunderstorm watch is issued by the
National Weather Service when the weather conditions are such that a severe thunderstorm
(damaging winds 58 miles per hour or more, or hail three-fourths of an inch in diameter or
greater) is likely to develop. This is the time to locate a safe place in the home and
tell family members to watch the sky and listen to the radio or television for more
information.
A severe thunderstorm warning is
issued when a severe thunderstorm has been sighted or indicated by weather radar. At this
point, the danger is very serious and everyone should go to a safe place, turn on a
battery-operated radio or television, and wait for the "all clear" from
authorities.
Learn how to respond to a tornado
and flash flood. Tornadoes are spawned by thunderstorms and flash flooding can occur with
thunderstorms. When a "severe thunderstorm warning" is issued, review what
actions to take under a "tornado warning" or a "flash flood warning".
D U R I N G
If indoors
Do not handle any electrical equipment or
telephones, because lightning could follow the wire. Television sets are particularly
dangerous at this time. Avoid bathtubs, water faucets, and sinks because metal pipes can
transmit electricity.
If outdoors
Attempt to get into a building or car. If no
structure is available, get to an open space, preferably low to the ground, as quickly as
possible. (If in the woods, find an area protected by a low clump of trees - never stand
underneath a single large tree in the open.) Stay away from natural lightning rods such as
golf clubs, tractors, fishing rods, bicycles, or camping equipment. Kneel or crouch with
hands on nees. Stay away from rivers, lakes, or other bodies of water.
If in a car
Pull safely onto the shoulder of the road away
from any trees that could fall on the vehicle. Stay in the car and turn on the emergency
flashers until the heavy rains subside.
Estimating the Distance from a Thunderstorm
Because light travels so much faster
than sound, lightning flashes can be seen long before the resulting thunder is heard.
Estimate the number of miles you are from a thunderstorm by counting the number of seconds
between a flash of lightning and the next clap of thunder. Divide this number by five.
Hail
Hail is produced by many strong
thunderstorms. Hail can be smaller than a pea or as large as a baseball, and can be very
destructive to plants and crops. In a hailstorm, take cover immediately. Pets and
livestock are particularly vulnerable to hail, so bring animals into a shelter.
A F T E R
Check for injuries. A person who has been
struck by lightning does not carry an electrical charge that can shock other people. If
the victim is burned, provide first aid and call emergency medical assistance immediately.
Look for burns where lightning entered and exited the body. If the strike caused the
victim's heart and breathing to stop, give cardiopulmonary resuscitation (CPR) until
medical professionals arrive and take over.
Report downed utility wires. Drive only if
necessary. Debris, downed wires, and washed-out roads may make driving dangerous.
BACKGROUNDER: THUNDERSTORMS AND LIGHTNING
EMERGENCY INFORMATION 
- Thunderstorms can bring heavy rains (which can cause flash flooding), strong winds,
hail, lightning and tornadoes. In a severe thunderstorm get inside a sturdy building and
stay tuned to a battery-operated radio for weather information.
- Lightning is a major threat during a thunderstorm. In the United States, between 75 to
100 Americans are hit and killed each year by lightning. If you are caught outdoors, avoid
natural lightning rods such as tall, isolated trees in an open area or the top of a hill
and metal objects such as wire fences, golf clubs and metal tools.
- It is a myth that lightning never strikes twice in the same place. In fact, lightning
will strike several times in the same place in the course of one discharge.
DID YOU
KNOW...
- At any given moment, nearly 1,800 thunderstorms are in
progress over the surface of the earth.
- On average, the United States gets 100,00 thunderstorms each year.
Approximately 1,000 tornadoes develop from these storms.
- Large hail results in nearly $1 billion in damage to property and
crops.
- The power of lightning's electrical charge and intense heat can
electrocute on contact, split trees, ignite fires and cause electrical failures.
- More deaths from lightning occur on the East Coast. More forest
fires are started in the West as the lightning season coincides with the dry season there.
- Approximately 10,000 forest fires are started each year by
lightning.
- Approximately $100 million in annual losses result from forest and
building fires caused by lightning.
- Straight-line winds exceeding 100 mph are responsible for most
thunderstorm damage.
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Thunderstorms...and their offspring
Thunderstorms affect
relatively small areas when compared with hurricanes and winter storms. The typical
thunderstorm is 15 miles in diameter and lasts an average of 30 minutes. Nearly 1,800
thunderstorms are occurring at any moment around the world. That's 16 million a year!
Despite their small size, all thunderstorms are dangerous.
Every thunderstorm produces lightning, which kills more people each year than tornadoes.
Heavy rain from thunderstorms can lead to flash flooding. Strong winds, hail, and
tornadoes are also dangers associated with some thunderstorms.
Of the estimated
100,000 thunderstorms that occur each year in the United States, only about 10% are
classified as severe.
Your National Weather Service considers a
thunderstorm severe if it produces hail at least 3/4-inch in diameter, wind 58 mph or
higher, or tornadoes.
Take time NOW to understand these dangers and learn basic safety
rules!
Flash Floods/Floods
The #1 thunderstorm killer...nearly 140 fatalities each year.
- Most flash flood deaths occur at night and when people become trapped in automobiles.
Lightning
Occurs with ALL thunderstorms.
- Averages 93 deaths and 300 injuries each year.
- Causes several hundred million dollars in damage to property and forests annually.
Straight-line Winds
Responsible for most thunderstorm wind damage.
- Winds can exceed 100 mph!
- One type of straight-line wind, the downburst, can cause damage equivalent to a strong
tornado and can be extremely dangerous to aviation.
- During the summer in the western states, thunderstorms often produce little rain but
very strong wind gusts and dust storms.
Large Hail
Causes nearly $1 billion in damage to property and crops annually.
- Costliest United States hailstorm: Denver, Colorado, July 11, 1990. Total damage was
$625 million.
Tornadoes
Nature's most violent storms.
- Winds can exceed 200 mph.
- Result in an average of 80 deaths and 1,500 injuries each year.
- Most fatalities occur when people do not leave mobile homes and automobiles.
This site is provided by the
Bainbridge Township Fire Department for the community that we faithfully serve.
Please contact Asst.
Chief Bill Lovell with any bugs, comments or suggestions for
improvement so that we can make this site more beneficial.
Last
Revision: 10/27/08 
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