Severe Weather Awareness

Severe Weather Awareness - Lightning

Lightning is found with every thunderstorm. While the lightning displays may be impressive to watch...they are also deadly!

Each year lightning causes an average of 93 deaths and 300 injuries in the United States.

Lightning has been responsible for damage, deaths and injuries while people were involved in all of these activities:

At ball games	Playing Golf	At a family reunion	Using a bank ATM
At a campground	While jogging	Standing by a refrigerator	Talking on a cordless phone
While canoeing	In their living room	At a rodeo	Walking along a beach
In cars	On motorcycles	While cleaning a storm drain	Looking out the window
In a garage	Outdoors	At a prison	Numerous animals have been killed and injured

Map of lightning casualties across the United States:
From Lightning Fatalities, Injuries and Damage
Reports in the United States, 1959-1994
[D]

Authors of Lightning Fatalities, Injuries and Damage Reports in the United States,1959-1994:
E. B. Curran, R. L. Holle and R. E. Lopez.
published by National Weather Service, Scientific Services Division, Ft Worth, TX. This report is officially known as NOAA tech memorandum NWS SR-193

Lightning also causes several hundred million dollars in damage to homes, businesses, churches, barns, and forests each year.

Millions of dollars in property loss are the result of lightning caused fires
Photo by Phoenix Gazette

Lightning step leader, positive leader, and return stroke

Within the thunderstorm clouds, rising and falling air causes turbulence which results in a build up of a static charge. The negative charges concentrate in the base of the cloud. Since like charges repel, some of the negative charges on the ground are pushed down away from the surface, leaving a net positive charge on the surface.

Opposite charges attract, so the positive and negative charges are pulled toward each other. This first, invisible stroke is called a stepped leader.

As soon as the negative and positive parts of the stepped leader connect there is a conductive path from the cloud to the ground and the negative charges rush down it causing the visible stroke.

Thunder is caused
by the extreme heat associated with the lightning flash

In less than a second, the air is heated to
15,000 to 60,000 degrees. When the air is heated to this temperature, it rapidly expands. When lightning strikes very close by, the sound will be a loud bang,
crack or snap. The duration of the
thunder associated with a nearby
lightning strike will be very short.
Lightning which strikes farther away will
rumble for a longer period of time as the sound arrives at different times due to the length of the lightning flash (typically many miles long).

Thunder can typically be heard up to 10 miles away. During heavy rain and wind this distance will be less, but on quiet nights, when the storm is many miles away, thunder can be heard at longer
distances.

"Flash to Bang"

You can estimate the distance to a thunderstorm using the "Flash to Bang" (time from seeing lightning until your hear thunder) by counting the seconds between the lightning "flash" and the "bang" of thunder. Each five seconds equals one mile. If you count 15 seconds, the flash was 3 miles away and you know that you are in a high danger zone. Six miles is still in the high danger zone.

Lightning can strike many miles from the parent thunderstorm - so when should you seek a safe shelter? The best answer is also the easiest to remember -

"If you can see it,
if you can hear it -
flee it!"

time sequence photo of numerous lightning strikes

When is it safe to resume activities after a thunderstorm?

Wait at least 30 minutes after the last thunder is heard before going back outside.

Most lightning deaths and injuries occur when people are caught outdoors. . If caught outdoors during a thunderstorm and no shelter is nearby...find a low spot
away from trees...fences...and poles. If you are in the woods...take shelter under the shorter trees.

Tents, and taking shelter under tall tress give no protection from lightning.

The safe skipper heads to a safe port when thunderstorms loom

If you are boating or swimming...get to land and find shelter immediately

You may not be able to hit a 2 iron - but lightning can!

You should also get out of open areas...such as golf courses...baseball diamonds and soccer fields during thunderstorms.

Open playing fields are no safe place during a thunderstorm.

If you feel your skin tingle or your hair stands on end...squat low to the ground on the balls of your feet. Places your hands on your knees with your head between them. Make yourself the smallest target possible and minimize your contact with the ground.

The "safe" lightning position is low to the ground, balanced on the balls of your feet, with your hands on your knees, and your head between your knees

These two brothers didn't recognize the danger they were in. Their hair is standing on end from a thunderstorm-induced electrical charge. The two brothers, and their sister, were killed moments later when lightning struck.

moments after this photo was taken, these young people were killed by lightning.

One myth about lightning is that people struck by lightning carry an electrical charge and shouldn't be touched.

FACT: Lightning strike victims carry no electrical charge and should be attended to immediately! Call 911 or the local emergency number for advanced medical care immediately. CPR should be started if necessary. Contact your local American Red Cross for information on CPR and first aid classes.

Contact your local American Red Cross chapter to learn CPR!

The Myths

1. If it isn't raining, then there is no danger from lightning.

2. The rubber soles of shoes or rubber tires on a car will protect you from being struck by lightning.

3. "Heat lightning" occurs after a very hot summer day and poses no threat.

The Facts

1. Lightning often strikes outside of heavy rain and may occur as far as 10 miles from any rainfall!

2. Rubber soles and rubber tires provide NO protection from lightning. The steel frame of a hard-topped car provides increased protection if you aren't touching metal. Although you may be injured if lightning strikes your car, you are much safer inside a car than outside.

3. What is called "heat lightning" is actually lightning from a thunderstorm too far away for thunder to be heard; however, the storm may be heading in your direction!

In recent years...sophisticated lightning detection equipment has monitored cloud-to-ground lightning strikes. This coupled with the new Doppler radar and high-resolution satellite enables the National Weather Service to keep you more informed during thunderstorms.

Be sure to stay tuned to NOAA Weather Radio during thunderstorms for the latest information.

With new equipment capable of monitoring and tracking lightning, stay tuned to official news sources for latest information.

Contact us if you'd like a free copy of Thunderstorms...Tornadoes...Lightning...Nature's Most Violent Storms - a preparedness brochure produced by the National Weather Service, Federal Emergency Management Agency, and the American Red Cross.

Related Web Sites on Lightning and Lightning Safety:

Tornadoes

Thunderstorm
Safety

Lightning
Safety

Flash Floods and River Floods

Hail

Downbursts/
Microbursts