Damage and Impacts
Lightning losses
While it is difficult to quantify lightning losses, it is estimated that $4-5 billion damage occurs each year. Likewise, the cost of lightning protection to safeguard critical equipment and facilities from lightning strikes during severe weather is enormous.
Lightning - the most dangerous and most frequently encountered weather hazard most people experience each year - is the second most frequent weather-related killer in the United States. About 100 people lose their lives and more than 500 are injured by lightning every year. Most casualties result from inappropriate behavior during thunderstorms, particularly when people are caught outdoors during recreation or organized sports. Being aware of - and following - proven lightning safety guidelines can greatly reduce the risk of injury or death.
What does lightning do to people?
This woman might not be laughing if she understood her risk of being struck by lightning was incredibly high. Her "electrified" hair should have been a dead giveaway that lightning from a nearby mountain thunderstorm put her life in extreme danger.
Cloud-to-ground lightning can kill and injure people by direct or indirect means. It is not known if all people are killed who are directly struck by the flash itself. The lightning current can branch off to a person from a tree, fence, pole, or other tall object. In addition, flashes may conduct their current through the ground to a person after the flash strikes a nearby tree, antenna, or other tall object. The current also may travel through power or telephone lines to a person who is in contact with electric appliances, tools, electronics, or a corded telephone. Lightning can also travel through plumbing pipes and water to a person in contact either with a plumbing fixture or a person in water, including bathtubs, pools, and the running water of a shower.
Damage to the human body:
Lightning affects the many electrochemical systems
in the body. People struck by lightning can suffer from nerve damage, memory
loss, personality change, and emotional problems. There is a national support
group for lightning and electric shock survivors.
An example is some single nerve cells, such as those extending from the brain to the foot, can be as long as 6 feet or more. These types of cells are most prone to lightning damage due to the instantaneous potential difference across the length of the cell as lightning begins to enter the body.
The intense heat of the lightning stroke can turn sweat instantly to steam and the tremendous pressure of the steam has been known to blow people's boots, shoes, and clothing off them. In places where metal is in contact with or close proximity to the body, such as jewelry or belt buckles, burn marks are found. Likewise, burn marks are found in places where the body had been sweaty, such as the feet, underarms, and chest.
How to stay safe when lightning is around - "If you can hear it, fear it!"
The best defense is plan ahead and avoid exposure to lightning when a thunderstorm occurs. Know where safe shelter is located and leave enough time to reach safe shelter before your danger level is high. Don't be an isolated tall object, and don't be connected to anything that may be an isolated tall object.
USE THE 30-30 RULE!
|
HOW DOES NSSL CONTRIBUTE?
NSSL researchers are active in promoting lightning safety education. One reason for this is that lightning is a single-victim event, unlike flash flooding which can kill many people at one time. Since it is not possible to issue specific warnings for every lightning flash for each person, researchers feel compelled to provide tools to help people protect themselves from lightning danger.
NSSL's scientists and collaborators did a study to find out how close is "too close" for lightning. They found that 80% of the next lightning strikes in a storm are within 2 to 3 miles of each other in certain weather conditions in Florida, but more typically lightning strikes are about 6 miles from each other. Their research was incorporated into a paper on updated recommendations for lightning safety which set forth some simple concepts for lightning safety:
- Flash-to-Bang
They helped develop a method to determine how far away lightning is occurring, called " Flash to Bang." When you see the FLASH, count the seconds to the BANG. Every 5 seconds equals 1 mile. Divide by 5 to give the distance in miles from you to the lightning. - 30-30
rule
They also helped come up with another rule: If you count to 30 or less between the flash and the bang, you are in danger and should go to safe shelter. Then, wait 30 minutes from the last flash or thunder to establish "all clear."
Posters
Taking shelters under trees is dangerous - recent
studies of lightning victims showed several highly-vulnerable situations
and activities, but the one that stood out was taking shelter under trees.
NSSL scientists developed posters on this threat, called "LIGHTNING DANGER!
STAY AWAY FROM TREES DURING THUNDERSTORMS!" Over 16,000 copies have been
printed in English and Spanish. The posters were distributed to teachers,
NWS staff, and others.
Lightning policy for sports associations
NSSL scientists
gave valuable input to the NCAA Committee on Competitive Safeguards and
Medical Aspects of Sports as they developed guidelines for lightning
safety at NCAA sporting events. They also helped create a position statement
regarding lightning safety for athletics and recreation for the National
Athletic Trainers' Association
Protecting WSR-88Ds from damage
NSSL worked with
the NWS to carefully evaluate the performance on the WSR-88D lightning
protection system and make recommendations for improvement. Part of the
process included creating a 3-D computer simulation of a cloud-to-ground
lightning stroke striking a radar antenna tower.