FAQ's_____________________________________________________________
How does lightning form?
Rapidly rising air in a thunderstorm interacts with rapidly falling air within the thunderstorm to create separately positive and negative charged areas within the cloud. Air acts as an insulator, but when the charge builds up to a level that exceeds its ability to act as an insulator, the result is a spark we see as lightning. The lightning equalizes the positive and negative charged areas.
Several types of lightning are common:
* In-cloud lightning extends from one charged region of a cloud to another
* Cloud-to-cloud lightning extends between two clouds
* Cloud-to-air lightning extends from a cloud to the air, not touching the ground
* Cloud-to-ground lightning stretches from a cloud to the ground
There are two ways of looking at lightning's direction:
1. Upward streamers: Lightning starts in a cloud when there is an updraft reaching subfreezing temperatures. A cloud-to-ground flash starts at around 15,000 feet during summer in the US. It travels toward the ground in 50-yard steps - this is the downward "leader". At the ground, there are small, upward "streamers" reaching upwards toward the electrified cloud. When the downward leader connects with the upward streamer, the bright light that we call lightning is visible, and moves upward. The way to think of it is that charge is lowered but current flows upward. This happens in a split second, so it's difficult to see.
2. True ground-to-cloud lightning: In some cases, the cloud area where lightning usually originates (15,000+ feet high) can be so low, like in a winter storm, that very tall natural (mountains) or man-made objects (towers or skyscrapers) sort of interfere with the initial charge moving downward toward the ground. Instead, the very tall object actually triggers the lightning, and the strike with its steps, forks, and branches truly appears to go upward. This is an unusual lightning event that we don't see every day, but there are photos that document it.
What causes thunder?
The air in the lightning strike is heated very rapidly and expands, creating a shock wave we hear as thunder. Thunder lasts a few seconds because we first hear the shock wave from the portion of lightning closest to us and then we continue to hear the shock wave from the lightning bolt farther away from us that is reaching us at later times.
How far can lightning travel?
Typically, lightning travels 10 miles or less. However, lightning has been observed to travel 20 miles or more, often extending up to 10 miles away from the cloud that formed the lightning.
How hot is lightning?
Within the lightning bolt the air is superheated to temperatures exceeding 50,000°F, many times hotter than the surface of sun.
How can I protect my small business and home computers, TV, and other electronics from lightning?
Lightning damage to small office and home electronics usually occurs when lightning strikes nearby utility poles or wires, then enters the building through power, phone and cable connections. For direct and indirect lightning hits, the only sure way to protect equipment and data, is to “pull the plug” on all electrical paths until the storm passes. Storm Shelter® products contain a specially designed disconnect mechanism that automatically provides true circuit isolation whenever lightning threatens. Once the storm has passed, and local lightning is no longer detected, all electrical connections are automatically restored.
Should I really be concerned about the chances of being struck by lightning and why is knowing where lightning strikes more important today?
At any time, 2,000 thunderstorms are occurring around the world, producing lightning that strikes the earth up to 100 times every second. Every time it reaches the earth's surface, it makes an enormous impact, causing power and telecommunications outages, forest and building fires, damage to aircraft and sensitive electronics, and deaths. The better we can pinpoint lightning, the better we can reduce its negative impact. We know that over 20 million flashes strike the ground in the United States every year. And most of them hit more than one point on the ground. While the problems caused by lightning often happen to one person or to one building at a time, it adds up to cause as much damage and as many casualties as any other storm hazard. One of the major reasons why lightning has become more important in recent years is our tremendous reliance on computers and technology, even in our homes and small businesses. Today in the information age, irreplaceable data is at risk. Entire businesses can be reduced to a standstill by the loss of data that no insurance company can replace. Viewed in this context and with so much more money due to information loss at stake, the new StrikeUPS power protection device is fast becoming the latest necessity for protecting valuable small business investments.
What are the odds of being a lightning victim?
With about 1,000 lightning injuries and deaths each year in the United States and a population of about 240 million, your the odds are 1 in 240,000 each year. Over an 80-year lifetime, your chance of being a lightning victim during your life is 1 in 3,000. You have a about a 1 in 300 chance of being affected by a lightning death or injury of a close friend or a relative. Now, buildings and utility poles are a different story and these are the primary conduits for losing valuable electronics and data. There are no hard statistics on the odds of your small business or home office being "fried", but the reasonable and unanimous consensus among prediction experts is that the odds dramatically increase. Virtually everyone has experienced power outages in their lives. And statistics point to over a billion dollars in lightning damage alone in 2002.
How does Storm Shelter®’s lightning detection work?
Lightning strikes give off specific electromagnetic signatures at certain frequencies which can be accurately interpreted by means of sophisticated sensors. Our products detect lightning threats in one of two different ways:
- Through compact, on-site lightning detectors, which accurately interpret the electromagnetic signature that lightning propagates.
- Through real-time data supplied by national lightning detection networks.
What is Storm Shelter®’s joule rating?
A joule is a measurement of energy expended in applying a force through a certain distance, or in passing a current of 1 ampere through a resistance of one ohm for one second. Because Storm Shelter completely removes the conductive path, Storm Shelter’s joule rating is infinite, when in a disconnected state. However, for those who like numbers, we simply claim protection in excess of 1 million joules.
Can Storm Shelter products protect against direct lightning strikes?
The answer depends largely upon the application involved. Indoor applications are much easier to protect. Modern building wiring is designed to “break down electrically” at 6000 volts, so any excess voltage caused by lightning, can be routed to ground. This means 6,000 volts is the maximum voltage surge that lightning can deliver to plugged-in equipment. Storm Shelter’s proprietary disconnect mechanism, provides a full .75 inch air-gap, affording electrical protection in excess of 20,000 volts.
Does having Storm Shelter equipment guarantee I won’t have lightning issues?
A: Storm Shelter products will effectively do their job, whenever lightning is detected. Storm Shelter’s criteria for disconnection is two strikes detected within a 5 minute period of time, with one of those strikes being within 3 miles of the detector. There are certain rare situations, where a user could be the recipient of the very first lightning strike within an area. Also, lightning damage can occur through any conductive path. To properly protect equipment, all conductors must be disconnected. Because of those possibilities, Storm Shelter cannot guarantee that a user will not experience lightning damage. It does guarantee that its products will work as designed.
How does Storm Shelter’s Preemptive Power, EPS-1 generator product protect loads from lightning?
When the EPS-1 detects lightning threats, it instructs the ATS to start the generator. Once reliable generator power is established, the ATS will transfer the power off of utility line power. Storm Shelter exploits the inherent isolation capabilities the ATS to protect the load from lightning strikes to the power line.
Does the EPS-1 product protect generator loads from direct lightning strikes?
The vast majority of lightning damage to loads, comes through strikes to the power-line. Storm Shelter’s EPS-1 exploits the ATS to act as barrier against those power line strikes. Since the load is on the “other side” of the ATS “barrier”, the load cannot be protected from a direct strike.
Does sheet lightning pose the same threat as bolt lightning?
The term sheet lightning generally refers to long channels of lightning that appear horizontal. This is often seen at the base of clouds in the 10,000- to 15,000-foot range, and may be at the bottom of a thunderstorm's anvil cloud. The horizontal--or sheet--portion of the flash may strike the ground some distance away. Think of the flash as having an upside down "L" shape, where there is a connection to ground and a long horizontal section along the base of a cloud. Flashes have been observed by special lightning detection systems that have one ground strike point that is connected to a horizontal segment up to 54 miles (90 kilometers) long!
How many people are struck by lightning?
In the United States, lightning kills 75 to 100 people each year. Lightning safety experts estimate that there are 10 times as many lightning-related injuries as deaths, totaling several hundred to a thousand injuries each year. Some of these injures are reported to authorities; many are not. To find out more, visit the National Weather Service Natural Hazard Statistics or the Lightning Strike and Electric Shock Survivors International.
Is it safe to use the telephone during thunderstorms?
Corded telephones are not safe and should not be used during thunderstorms. The usual way that current enters a telephone is through the wire. Cloud-to-ground flashes tend to hit tall objects such as utility poles. When a pole is struck, its current enters a building through the wiring, then to the phone, and then straight to your head. Cell phones and cordless phones are safer, but be sure to stand away from the cordless phone's base as a strong current can possibly arc a few feet from the base to the handset. There is still a risk of ear damage from loud static and "pops" associated with cell phone and cordless phone use during thunderstorms.
Are headsets safe to use during thunderstorms?
No, is not safe to use any devices that have can conduct electricity from outside the building to inside the building. That includes telephone headsets, stereo headsets, TV video games, and your computer's keyboard. Wiring is made to conduct electricity to you, including lightning's strong electrical current.
Should I keep all windows in my home closed to keep lightning from traveling into my house?
It doesn't make much difference if windows are open or closed when lightning is occurring. It's the window's frame that matters when it comes to lightning. If the window frame is metal, lightning current can easily travel through it and can injure a person touching it. So, it is a bad idea to be touching or closing them during a thunderstorm. Of course, lightning is Mother Nature's warning sign of severe weather. Lightning may not come through your window, but during a thunderstorm's high winds or microbursts, a patio chair can. So, stay away from windows. Also, it used to be recommended that windows should be opened to "equalize pressure" when a tornado is approaching, this has been proven wrong. Close your windows and doors at the first signs of approaching thunderstorms.
What are "positive" and "negative" strikes?
The sign--or polarity--of a lightning strike depends on what type of charge is lowered to ground. A negative cloud-to-ground flash means that negative charge is lowered to ground. In this case, excess negative charge occurred aloft in a thunderstorm, often at about 20,000 feet above sea level, and negative charge was brought down to the ground by the flash to try to equalize the electrical imbalance. Usually, the layering of charge is such that negative charge builds up closer to the ground than positive charge, so negative charge lowers more readily to the earth's surface. About 95% of all cloud-to-ground flashes worldwide are negative. In the case of positive charge, the positive charge is brought to ground, but this usually happens near the end of storms, in winter storms, and on the edge of large thunderstorm complexes. Although less frequent, positive strokes generally contain more current and are more apt to catch more people by surprise.
Can we use the energy in lightning as an alternate power source?
Capturing the energy of lightning is intriguing, but not yet feasible for several reasons. First, no one knows exactly where to collect lightning as it does not naturally strike specific places more than a few times a year. Next, conventional storage devices for electricity--like a battery--do not accommodate the magnitude and duration of a powerful flash that lasts only fractions of a second. Finally, about half of the energy of a lightning strike dissipates into light, acoustic energy, and electromagnetic waves. There are ongoing studies to explore the use of laser beams to control lightning. It appears possible that a laser beam can be sent into an electrified cloud to trigger lightning which could then be, in theory, captured.
Is marine life killed or injured when lightning strikes in an ocean?
When lightning hits open water, the current is able to travel through the water quite well. How far away the dangerous current travels is not known, but it's probably on the order of tens of yards. At and very near the strike point--within a few yards--current enters the body of a living organization, resulting in injury or death. At greater distances, the effects are less, so that the current might stun an organism but not kill it. There are few reports of massive fish kills. It may be that there are not too many fish in any single volume in the affected water, they may recover quickly, or maybe larger fish eat the incapacitated fish.
Why is the launch of the shuttle delayed because of bad weather, when commercial airliners take off and land in thunderstorms and lightning?
The shuttle is quite different from a commercial airliner. The shuttle launches straight up through any clouds that are there. Airliners sometimes fly through clouds, but they can avoid the worst ones. Rocket exhaust plumes stretching from the shuttle (or other rockets) to the ground makes an excellent lightning rod and therefore lightning is drawn especially to a flying rocket. This is very dangerous. The shuttle has a fragile and critical thermal tile skin that must be intact for re-entry. Lightning strikes would probably shatter thermal tiles. The shuttle also uses extremely explosive hydrogen and oxygen for fuel. A lightning strike on or near the launch pad or during flight could cause this propellant to explode. An airliner uses a kerosene-like fuel which is far less flammable. Airliners can land in the rain, but even they often delay or divert to avoid severe thunderstorms.
How can you tell how far away lightning is?
It takes five seconds for sound to travel one mile. When you see a flash, count the number of seconds between until you hear the thunder and then divide by five to get the number of miles between the lightning and you. National lightning safety experts agree a good rule of thumb is if you count 30 seconds or less between the flash and thunder, you are in immediate danger and should seek safety.
Do tires in a car or rubber soles on shoes protect you from lightning?
No. The lightning has traveled many miles to reach you; the extra inch of rubber offers no protection. The inside of a car is safer because the lightning travels around the car's metal frame to the ground. Rubber soles on shoes offer no protection from lightning.
How can I protect myself from lightning?
People who spend much of their time outside are most at risk being struck by lightning. Golfers, fishermen, and hikers are most prone to being struck. Anyone who works outside, such as a construction worker, is also at risk. You can avoid being struck by immediately seeking shelter inside a substantial building or metal-topped vehicle when lightning is present. Never seek shelter outside under a tree. It's better to be wet from rain than dead or disabled by lightning. When inside and lightning is nearby, do not use electrical appliances, including computers and video games connected TV sets, telephones, or have contact with running water or water pipes. Electricity from lightning can travel through phone wires, electric wires, TV cables, and plumbing.
If I can't reach shelter how do I protect myself?
As a last resort, make yourself as short as possible with as little contact with the ground as possible. Lightning usually strikes the tallest objects such as trees, utility poles, and metal objects. Do not seek shelter under trees, utility poles, near metal fences or gates. Go to a low spot, but avoid washes and places where water will collect, crouch down on the balls of your feet and make yourself into as small a ball as you can. Do not lay down or sit on the ground. Lightning currents can travel across the ground so you want to make as little contact with the ground as possible.
How close to a thunderstorm can you be and remain safe?
In urban areas, buildings and city noise reduce your ability to hear thunder until it's only 10 miles away or less. Since lightning can easily travel 10 miles away from a thunderstorm, if you're in a city and can hear thunder, you are at risk from being hit by lightning. In quiet, rural areas, thunder can be heard from thunderstorms that are up to 15 or more miles away. The best course of action is to remain alert to your weather surroundings. Be aware of new thunderstorms forming near you as other thunderstorms are leaving the area.
Where does the most lightning occur in the United States?
Year in and year out, the hot spot for the most lightning per square mile is in central Florida. Other lightning hot spots vary from year to year, but in Gulf Coast areas of northwest Florida, Alabama, Mississippi, Louisiana, and east-central Texas usually trail central Florida in strike density.
Is there much lightning in tornadoes and hurricanes?
Tornadoes can have a wide variety of lightning. Some closely-observed tornadoes had no thunder at all from the storm during the tornado. But usually, the parent storm eventually produces a fair amount of lightning. Hurricanes usually have very little or no lightning. The only significant lightning is observed in the outer rain bands. Probably less than 10% have more than a few cloud-to-ground flashes in the eye wall. Data on in-cloud flashes during hurricanes is scarce. Why there is so little lightning in the core of hurricanes has been the subject of conjecture. It probably has to do with the strong horizontal winds not allowing much vertical mixing compared to a more isolated storm.
Is lightning attracted to water or other objects on the ground?
A cloud-to-ground flash usually begins in a cloud at 15,000 to 20,000 feet above ground. It comes to earth in 50-yard steps. Until it's close to the ground, it has no idea of what it will hit. Then, within 30 to 50 yards of the ground, lightning decides what is the best connection to make with the surface. Often, the best connection is the tallest object within the 30 to 50 yard area.
_________________________________________________________________________
