Rash of Lighting Strikes Hits Forsyth County

Posted Monday, July 18, 2005

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Lightning, the number two storm killer in the U.S. according to the National Lightning Safety Institute, has struck Forsyth County hard recently. The Forsyth County Fire Department has responded to multiple lightning-related incidents in recent weeks.

In the last two days alone, two structures incurred significant strikes. Additionally, two fishermen were injured when lightning struck their boat on Lake Lanier Thursday evening.

A house at 2965 Winchester Drive was struck by lightning on Wednesday. A storage building received significant fire damage when lightning hit a pine tree close by, grounding out in the nearby building. The residence itself received only minor damage thanks to a quick response by the Forsyth County Fire Department.

On Thursday, a second house, located at 2463 Pitman Circle, was struck, again when lightning from a nearby tree jumped to the nearest structure – in this case the residence. The house received moderate structural damage as well as losing portions of its siding and receiving damage to an interior living room.

A fishing boat on Lake Lanier was struck by Lightning just after 7:00 pm Thursday. The two men on the boat were transported to Grady Memorial Hospital in Atlanta. According to hospital officials, one of the men is listed in stable condition. The other was treated and released.

Captain Jason Shivers of the Forsyth County Fire Department urges all citizens to exercise caution and sound judgment during the summer storms, which are so common in the area.

“Cloud-to-earth lightning will always find a ground,” said Shivers. “Always be aware of the atmosphere and the current and expected weather conditions.”

“Lightning is possible many miles away from the nearest thunderhead or rain storm,” continued Shivers. “The sound of thunder or existence of rain is not required for lightning strikes to occur.”

According to the National Weather Service, summer is the peak season for lightning - one of the nation's deadliest weather phenomena. In the United States, an average of 67 people is killed each year by lightning -- more than the number of people killed annually by tornadoes or hurricanes. Many more are struck but survive. Survivors, however, often report a variety of long-term, debilitating symptoms, such as memory loss, attention deficits, sleep disorders, numbness, dizziness, stiffness in joints, irritability, fatigue, weakness, muscle spasms, depression and an inability to sit for long.

Preparedness and precaution are keys to lightning safety. The following safety tips are recommended by the Forsyth County Fire Department and provided by the Georgia Emergency Management Agency and the National Lightning Safety Institute.

PERSONAL LIGHTNING SAFETY TIPS

1. PLAN in advance your evacuation and safety measures. When you first see lightning or hear thunder, activate your emergency plan. Now is the time to go to a building or a vehicle. Lightning often precedes rain, so don't wait for the rain to begin before suspending activities.

2. IF OUTDOORS Avoid water. Avoid the high ground. Avoid open spaces. Avoid all metal objects including electric wires, fences, machinery, motors, power tools, etc. Unsafe places include underneath canopies, small picnic or rain shelters, or near trees. Where possible, find shelter in a substantial building or in a fully enclosed metal vehicle such as a car, truck or a van with the windows completely shut. If lightning is striking nearby when you are outside, you should:

a) Crouch down, put feet together and place hands over ears to minimize hearing damage from thunder.

b) Avoid proximity (minimum of 15 ft.) to other people.

3. IF INDOORS Avoid water. Stay away from doors and windows. Do not use the telephone. Take off head sets. Turn off, unplug and stay away from appliances, computers, power tools, & TV sets. Lightning may strike exterior electric and phone lines, inducing shocks to inside equipment.

4. SUSPEND ACTIVITIES for 30 minutes after the last observed lightning or thunder.

5. INJURED PERSONS do not carry an electrical charge and can be handled safely. Apply First Aid procedures to a lightning victim if you are qualified to do so. Call 911 or send for help immediately.

6. KNOW your emergency telephone numbers.

QUESTIONS AND ANSWERS ABOUT LIGHTNING

(Provided by the Georgia Emergency Management Agency)

1. What causes lightning?
Lightning originates around 15,000 to 25,000 feet above sea level when raindrops are carried upward until some of them convert to ice. For reasons that are not widely agreed upon, a cloud-to-ground lightning flash originates in this mixed water and ice region. The charge then moves downward in 50-yard sections called step leaders. It keeps moving toward the ground in these steps and produces a channel along which charge is deposited. Eventually, it encounters something on the ground that is a good connection. The circuit is complete at that time, and the charge is lowered from cloud to ground. The flow of charge (current) produces a luminosity that is very much brighter than the part that came down. This entire event usually takes less than half a second.

2. Where does lightning usually strike?
Lightning comes from a parent cumulonimbus cloud. These thunderstorm clouds are formed wherever there is enough upward motion, instability in the vertical and moisture to produce a deep cloud that reaches up to levels somewhat colder than freezing. These conditions are most often met in summer. In general, the U.S. mainland has a decreasing amount of lightning toward the northwest. Over the entire year, the highest frequency of cloud-to-ground lightning is in Florida between Tampa and Orlando. This is due to the presence, on many days during the year, of a large moisture content in the atmosphere at low levels (below 5,000 feet), as well as high surface temperatures that produce strong sea breezes along the Florida coasts. The western mountains of the U.S. also produce strong upward motions and contribute to frequent cloud-to-ground lightning. There are also high frequencies along the Gulf of Mexico coast westward to Texas, the Atlantic coast in the southeast U.S., and inland from the Gulf. Regions along the Pacific west coast have the least cloud-to-ground lightning. Flashes that do not strike the surface are called cloud flashes. They may be inside a cloud, travel from one part of a cloud to another, or from cloud to air.

3. Can lightning be detected?
Since the 1980s, cloud-to-ground lightning flashes have been detected and mapped in real time across the entire U.S. by several networks. In 1994, the networks were combined into one national network consisting of antennas that detect the angle from ground strike points to an antenna (direction-finder antenna), that detect the time it took for them to arrive at an antenna (time-of-arrival method), or a combination of both detection methods. The network is operated by Global Atmospherics, Inc. Flashes have also been detected from space during the past few years by an optical sensor. This experimental satellite covers the earth twice a day in tropical regions. The satellite also detects flashes that do not strike the ground, but cannot tell the difference between ground strikes and cloud flashes.

4. How many flashes are there?
Over the continental 48 states, an average of 20,000,000 cloud-to-ground flashes has been detected every year since the lightning detection network covered all of the continental U.S. in 1989. In addition, about half of all flashes have more than one ground strike point, so at least 30 million points on the ground are struck on the average each year in the U.S. Besides cloud-to-ground flashes, there are roughly five to ten times as many cloud flashes as there are to ground.

5. What types of damage can lightning cause?
Cloud-to-ground lightning can kill or injure people by direct or indirect means. The lightning current can branch off to a person from a tree, fence, pole or other tall object. It is not known if all people are killed who are directly struck by the flash itself. 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 or plumbing pipes to a person who is in contact with an electric appliance, telephone or plumbing fixture. Similarly, objects can be directly struck and this impact may result in an explosion, burn or total destruction. Or, the damage may be indirect when the current passes through or near it. Sometimes, current may enter a building and transfer through wires or plumbing and damage everything in its path. Similarly, in urban areas, it may strike a pole or tree and the current then travels to several nearby houses and other structures and enter them through wiring or plumbing.

6. How to stay safe when lightning is around.
Based on these types of dangerous situations, don't be an isolated tall object and don't be connected to anything that may be an isolated tall object. The best defense is to 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 the lightning threat is overhead.

One way to find the distance to lightning is to use the 'flash-to-bang' method. Count five seconds for every mile the lightning is away from you. Safe shelter must be reached completely in all situations before a flash is two to three miles away, which is 10 to 15 seconds flash-to-bang.

But there is often blue sky in some direction while lightning is occurring nearby and it may not be raining, so pay much more attention to the lightning than the rain. A particularly difficult situation is the first flash from a storm--watch for a storm that is growing quickly, such as when a storm is becoming very dark at its base or is growing very tall. An equally dangerous situation is when a storm appears to be finished and only light rain and/or occasional thunder are heard, but the cloud overhead continues to be fairly dark. The most common situation for a lightning death or injury in Florida was found NOT to be in the heaviest rain area with lots of flashes, but after or before the time when rain and lightning was the most intense. So, the weak storm without too many flashes, at the edge of a larger storm, or early or late in the life of a storm is most dangerous.

The best shelter is a substantial building that has plumbing and wiring--in other words, one that is used or lived in by people for a major portion of the day. A very unsafe building for lightning has only a roof and some supports, but no wiring or pipes extending into the ground. A vehicle with a metal roof provides good shelter, and is much better than being in the open or in an ungrounded building, but is not as good as being in a building that is grounded by wires and pipes.

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