Lightning Laboratory 2000

On May 6, 2000, Fox 35 News sponsored the Lightning Laboratory at Seminole Community College at Sanford, Florida. Chief meteorologist Janice Jones,

hosted the workshop.

The first speaker was Matthew Bragaw, the National Weather Service forecaster who is the local lightning focal point for the forecast office in Melbourne, Florida.

The second speaker was Mr. William P. Roeder, chief staff meteorologist and science and technical training officer for the 45th Weather Squadron at Patrick Air Force Base.

Randy Rauch, co-meteorologist for Fox 35 News at Ten, presented "Protecting your Property".

David Stillers, the Lightning Stalker, one of the most widely recognized photographers of lightning in the country, presented his works.

Details of the lightning meeting:

Janice Jones, Fox News Meteorologist, opened the meeting with a discussion of the lightning experts in the area. The first speaker was Matthew Bragaw, Weather forecaster. He discussed the phenomenology of lightning storms. There is a counter-current with the falling ice particles striking the rising water molecules, and electrons move from the ice to the water around the zero degree Celsius line of air temperature. The rising negative electron charges in the cloud carry the electrons to the cloud top while ground charges become more positive with the cloud base being negative. Lightning step leaders descend in spurts of about 150 ft. each. These leaders keep advancing with as many as 10,000 steps for a stroke. The positive ground charges coming in as the leader descends eventually cause positive streamers that began rising from the ground. Other step leaders disappear at the instant of connection, and the primary stroke follows the positive stream that it has reached. At this point, charges are moving up into the cloud. There are also dark leaders, which have very low luminance. Negative lightning strikes occur from these leaders.

The first cloud strike can occur from the extended anvil or drifted top of the cloud. The positive leader will move down and negative streamers will rise from the earth. This occurs only about 10% of the time, but most of the power is in these strikes. These lightning bolts are most likely to kill and to occur where there is no rain.

In Central Florida, there are more lightning storms than anywhere else in the United States, thus it is the lightning capital of the USA. The world record is held by Uganda. The typical lightning bolt as 30,000 amperes to 300,000 amperes. The average potential of all days is 100 million volts and produces a 50,000 degree Fahrenheit stroke. The brilliance of this stroke is about five times that of the sun. Under most conditions, thunder is audible to about 10 mi.. According to a map shown, the incidence of lightning strikes is about 0.75 strokes per square kilometer in Wyoming and 8 strokes per square kilometer near Palm Bay, Florida. Florida lightning storms occur over primarily over a period of four months of summer sea breeze storms.

There are three sources of thunderstorms: moisture, instability, and a source of lift that acts as a trigger. Doppler radar has improved so much now that a strong lightning storm will produce a circular pattern or outflow boundary caused from the outflow of air moved by the falling rain.

Much of the Florida storm phenomenon is caused by sea breezes that come in from the ocean and rise over the middle of the state. The Bermuda High gives us east winds. Winds from the southwest blow from the Gulf of Mexico. These prevailing winds push the sea breeze storm regions east or west over Florida. The east and west sea breeze collides, thus creating a principal line of thunderstorms. If there is a west coast wind from the Gulf, the sea breeze will push in farther, causing early afternoon eastern storms. If the Bermuda High is predominant, the storms are thus pushed to the west and can occur near Tampa. The shape of the western Florida coast line causes a convergence of winds that produces more storms in the area best known as "Lightning Alley" between Tampa and Titusville. Without prevailing wind, there is a more even distribution of the storms in midstate.

Lightning in Florida caused some 1523 injuries (1959-1994), while in Wyoming, some 104 injuries occurred. These are composites of injuries and deaths. From 1959 to 1994, Florida had 345 deaths and 21 deaths in Wyoming. In Florida, weather kills some 53 by lightning, 23 by drowning, 3.5 [statistically] by cold. From 1983 through 1990, 12 people died before the storm and 6 at the middle or height, and 16 died after the storm according to Holle, 1993. This is because people take shelter during the worst heart of the storm but will stay out when strikes are few. Some 13 were killed when there was less than one flash in four minutes, at the most frequent part of the storm, where flashes occurred in one in from 1 to 4 minutes, eleven were killed. After the storm, when there was less than one flash in eight minutes, eight were killed. Matthew Bragaw makes the analogy that this is like walking across the Interstate in that if many trucks are coming you will not cross, whereas if only one truck is coming, you may cross even though one truck would kill you just as dead.

There is a lightning rule called the 30-30 rule. Thunder sound travels more slowly than light, so counting the seconds between the flash and the bang gives one a way of the estimating the distance of the lightning stroke. The number of seconds divided by five gives the distance in miles. You should seek shelter when the sound delay is 30 seconds or less, and you should remain there until 30 minutes after the last thunder is heard or lightning is seen. With lightning storms, lightning is the first to arrive and the last to leave.

Lightning safety was discussed by Mr. William P. Roeder, Chief Staff Meteorologist of the 45th Weather Squadron at Patrick Air Force Base. There are four ways to reduce lightning death: forecasting, protection, mitigation, and education. A famous photo taken at Sequoia National Park shows a young man and girl standing smiling and laughing as the electrostatic charge makes their hair stand on end. An instant later, one of them was dead. Just a few feet away, their parents were taking the pictures.

There were three lightning survivors present at the conference. One had been disconnecting the antenna from the TV set when a lightning bolt entered the antenna line, went through his foot, and then from his body into the TV set. A young girl had been setting an alarm clock when she was struck. A fisherman had been fishing as a storm approach to using a carbon fiber rod, which had the pole tip disintegrated some two feet back into just a mass of the fiber.

Lightning is the second leading cause of weather death, but 90% or the victims survive, although 70% of them require long-term medical care. There is a six billion dollar impact in the US caused by lightning. The principal locations of lightning strikes harming people occur in open fields during water activities, under trees, or driving tractors. There is a lightning safety group that is developing NCAA safety guidelines although these are, of course, not 100% safe.

Telephones are efficient death machines in a lightning storm. Some 2.4% of deaths occur on the telephone, one-half the rate of those deaths that occur while golfing. The telephone wiring extends some four miles from a phone to the central office, and acts as an antenna to collect nearby lightning strokes and carry them to the handset, which is pressed against the user's head. In all, cordless phones are relatively safe in the lightning storm, but corded telephones should not be used.

The primary deaths and injuries due to lightning are from the side flash leaping from a tree to a person, steam explosion of trees which cause wooden splinters to fly into the nearby person, ground streamers 1 to 3 in. wide that can extend out some 15 ft. from the actual point of the strike, and an upward streamer which can rise 750 ft. higher to the downward strike making connection. On many occasions, lightning will strike to the ground rather than a 40 ft. metal pole that is only 50 ft. away. Lightning does not always strike on the peaks of mountains but often hits on the sides. As much as fifteen nautical miles from a storm, electrical charges in clear air can produce a bolt from the blue that does not even appear to come from a cloud.

In a forming storm, the first strike is a ground strike, so watching the sky to see the distant storm may give you an early warning. If you are trapped in an unsafe location, proceed to the nearest safest area. Signs of impending lightning are tingling skin, hair sticking out, and metal vibrating like zippers. When you are in a group, you should spread out several body lengths and crouch while covering your ears and keeping your feet close together. This will lower you close to the ground yet reduce the likelihood of current entering one foot going through the body and leaving by the other foot.

Suggested safety for small groups: Where less than ten minutes will allow you to reach shelter area, designate a weather monitor to be aware of incoming weather, focusing upon that to give a warning if storms move close. Remember when lightning threatens, you have a choice; seek a shelter area.

Move lightning victims to a safer area if needed. Give one cycle of CPR first, but if lightning is still in the area, one must get to a lower area away from where lightning is less likely to strike. For lightning victims, only about 10% are killed immediately by the lightning strike. This means 90% of the rest have a chance of revival if CPR (cardiopulmonary resuscitation) is started immediately.

Randy Raush, co-meteorologist for Fox 35 News at Ten, gave a presentation on protecting your property. Lightning accounts for over 100,000 computer losses amounting to $125 million in damages in 1997. A surge protector should have a clamping voltage of 400 volts or lower and a response time of less than ten nanoseconds. Randy showed a video of lightning protection specialists installing air terminals and with heavy wires to carry off lightning strikes to ground without damage to buildings.

The lightning stalker, David Stiller, began his career as a poet writing some 1200 poems. He then decided to take photography of the rising and setting sun. As he began taking photos of the moon, he also got photos of lightning. He then began to focus on the many lightning storms of central Florida, taking many photographs and selecting the very best to keep. He has an excellent website in which you may see many of these photographs. The astounding thing was that of the many that he showed to the group, he knew that date of each of them. He has given them poetic names such as "Peace", "Justice", "Energy ", and so forth. His creativity is captured in his message "Wouldn't it be great if... "

From www.oocities.org/Yosemite/1270/general/lightning2000.html updated 04/13/2001 by Frank R. Leslie