A bolt of lightning can travel at a speed of 45 km/s (kilometres per second) (100,000 mph, 160,000 km/h). It can reach temperatures approaching 28,000 °C (50,000 °F), hot enough to fuse soil or sand into glass channels.
An average bolt of negative lightning carries a current of 40 kA (kiloamperes), although some bolts can be up to 120 kA, and transfers a charge of 5 coulombs and 500 MJ (megajoules), or enough energy to power a 100 watt lightbulb for just under two months. The voltage depends on the length of the bolt: with the dielectric breakdown of air being 3 million volts per meter, this works out at about one billion volts for a 300m (100 yard) lightning bolt.
Different locations have different potentials (voltages) and currents for an average lightning strike. For example, Florida, with the largest number of recorded strikes in a given period, has a very sandy ground saturated with salt water, and is surrounded by water. California, on the other hand, has fewer lightning strikes (being dryer). Arizona, which has very dry, sandy soil and a very dry air, has cloud bases as high as 6,000-7,000 feet above ground level, and gets very long, thin, purplish discharges, which crackle; while Oklahoma, with cloud bases about 1,500-2,000 feet above ground level and fairly soft, clay-rich soil, has big, blue-white explosive lightning strikes, that are very hot (high current) and cause sudden, explosive noise when the discharge comes. The difference in each case may consist of differences in voltage levels between clouds and ground.
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