Gallery: The Science Behind Lightning's Electric Shows
Weather Studios01P86-supercell-storm
__Supercell Storm__ Thunderstorms form when warm air currents surge upwards to create the huge, menacing clouds you see on the horizon. Sometimes, the thunderclouds crowd together and march towards you in a group. But other times, a single thundercloud will suck up the air currents and turn into a supercell thunderstorm. Lasting for hours, these are incredibly strong storms, responsible for most significant tornadoes in the United States and for most hailstones larger than the size of a golf ball. In this photo, you can see lightning flashing within a supercell storm, illuminating small-globe shaped clouds called mammatus.
Martin A. Uman, University of Florida02P54-fulgurite
__Fulgurite__Lightning can heat the air around it from 18,000 to 60,000 degrees Farenheit. When super hot lightning hits sandy areas, it can create what’s called a fulgurite or “petrified” lightning. The intense heat zips down through the sand, melting the granules around it and creating narrow, hollow glass tubes. Contrary to what *Sweet Home Alabama* fans might think, the fulgurites don’t resemble clear, Chihuly glass art. This photo shows the University of Florida’s excavation of the world’s longest fulgurite at 16 feet.
United States National Weather Service/NASA03P87-world-map-of-lightning-flashes
__Global Map of Lightning Flashes__Created from satellite data, this map shows the frequency of lightning flashes from 1995-2003. Central Africa has the most lightning activity with thunderstorms gathering year round due to warm air masses rolling in from the Atlantic Ocean. In the eastern region of the Democratic Republic of Congo, the village of Kikufa experiences the most lightning of anywhere on earth: 61 lightning strikes per square mile per year.
Nathan Edwards04P95-downward-meets-upward-lightning
__Ribbon Lightning__ If the initial lightning strike doesn’t entirely dispel the electrical charge, other lightning strikes will burst through that channel. High winds will blow each successive lightning strike slightly to the side, creating the ribbon lightning effect.
Steve Hodanish05P96-lightning-with-two-very-far-apart-forks
__Forked Lightning__Drawn to separate pools of strong positive charges, forked lightning appears to hit the ground in two distinct locations. Usually, the forks are only a couple hundred feet apart. This spectacular strike in Colorado has two contact points abnormally far apart.
Matthew Clark06P102-3-lightning-underbrushing-thunderclouds
__Anvil Crawlers__Inner positive and negative charges can be strong enough to create lightning within a thundercloud, called cloud-to-cloud lightning. You can see the illumination of the clouds from the inside, and sometimes, the lightning will peek out of the bottom of the cloud, brushing the underlying cloud surface. These comparatively slow-moving lightning channels are called anvil crawlers, and you see them here tickling the underside of an anvil cloud in Denton, Texas.
El Caballero07P105-cloud-to-air-lightning
__Cloud-to-Air Lightning__When a big group of positively charged particles rises up near a thundercloud, the potential can be high enough to exchange electricity cloud-to-air style. Lightning snakes out into air, as if reaching for something and then...changes its mind.
Weather Studios08P107-lightning-from-an-anvil-cloud-Nebraska
__Superbolt__Occasionally, the positively charged top of the thundercloud will reach out to the negatively charged ground outside the thunderstorm footprint. These “superbolts” happen only about 5 percent of the time but are thought to be responsible for a large percentage of forest fires and power line damage. Since the charges have to meet each over such a great distance (the journey from the cloud to the ground can be more than 10 miles) the superbolt carries a huge voltage, more than 10 times that of normal lightning. As a result, the lightning flash lasts much longer.
Thordur Arason, Icelandic Meteorological Office09P118-volcano-lightning
__Volcanic Lightning__Lightning will also occur around other natural phenomena like volcanoes. Though scientists don’t yet agree on the details, one theory is that the chaos of the eruption creates electrical charge. As the billions of ash particles spurt into the air, crashing into each other, the friction between them charges the particles. Larger positive particles move down and smaller negative particles move up. When the difference between the charges reaches a tipping point, lightning will flash. This reddish lightning formed within the debris-laden air during the 2010 eruption of Iceland’s Eyjafjallajokull volcano.
USDA Forest Service, Southwestern Region10P119-wildfire-lightning
__Wildfire Lightning__Lightning can also create its own thunderstorm. When lightning starts a wildfire, the heat and smoke rising up from an intense wildfire can form a “dry” thunderstorm, called a pyrocumulonimbus storm. The atmosphere above the fire becomes charged enough to trigger more lightning, but these clouds rarely produce enough rain to put out the fire. The smoke particles get in the way of forming precipitation. You can see inner cloud lightning illuminating the middle of this pyrocumulonimbus at Kaibab National Forest in Arizona.
Elsevier11P131-Lichtenberg-figure
__Lightning and People__Every lightning strike is unique. Some people may suffer severe burns and others may walk away with the memory of an electric shock and a couple minor burns. Although lightning vibrates with voltage, it brushes over you for only a fraction of a second, usually not long enough to through your skin and turn you into a superconductor. The brushed, “flashover effect” shows up as branching patterns on skin, called Lichtenberg figures, like on this woman. Lightning struck her house while she had been talking on a corded phone. Not burns, these figures fade anywhere from a few hours to a couple days after the strike. Scientists think negatively charged electrons from the lightning rush into the skin, break down the skin cells and then radiate outward.
Steve Kay12P164-lightning-hitting-buildings-Brighton
__Lightning in the City__You can protect buildings from lightning damage in two ways. First, lightning rods on the roof capture the electrical charge and channel it safely through connected wires to the ground. Second, surge protectors plugged into your outlets protect electrical equipment from lightning-induced voltage surges that travel along telephone and electrical wires and ground cables. But lightning doesn’t care. In the United States in 2011, people made 186,000 insurance claims totalling $953 million for homes damaged by lightning. And as people have bought more electronics, the average cost per claim has increased, doubling since 2004.
Jane Burridge13P168-lightning-hitting-buildings-Hayling-Island
__Lightning on the Water__This is a lightning strike seen from Hayling Island in England. Before Benjamin Franklin invented the lightning rod in 1752, wooden ships had historically been an easy target. Lightning struck one British frigate, the Lowestoffe, three times in a row, splintering and setting fire to the ship. Many of the crew members died and the others survived with severe burns and paralysis. Most ships now are made from steel or iron, which capture the lightning charge and transfer it to the sea with no problem. But if you’re out fishing on the lagoon and a storm is rolling, you better start paddling.
Science Photo Library14P175-lightning-strikes-space-shuttle-launch
__Lightning and NASA__ Even if skies are clear, spacecraft and rocket launches can trigger lightning. Turns out, the exhaust plumes trailing the rockets are super good conductors, lowering the amount of differential charge needed to generate lightning. In 1969, NASA almost had to abort Apollo 12 when lightning struck the Saturn rocket. And NASA did abort an unmanned Atlas-Centaur rocket in 1987 when lightning burst through the fibreglass nose cone and fried the computer programming 51 seconds into the flight. As five to ten percent of lightning strikes happen in thunderstorm-happy Florida, the decision to base the launch pad was perhaps ... misguided. Between 1981 and 2011, one-third of weather-related launch delays were due to the possibility of plume-triggered lightning.
