A view of scenic North Scottsdale Arizona all the way up to Pinnacle Peak and Reata Pass. Lightning is hitting the desert floor around Reata Pass area from some very high thunderstorm monsoon clouds above. Lightning can occur with either positive or negative polarity; negative is more common, but positive lightning can carry ten times more current. In either case, the amount of voltage depends on the length of the bolt - the longer the bolt, the higher the voltage. Cloud-to-ground lightning bolts are a common phenomenon, about 100 strike Earth's surface every single second, yet their power is extraordinary. Each bolt can contain up to one billion volts of electricity. Lightning can heat the surrounding air to thousands of degrees. This causes the air to expand rapidly which generates a supersonic shock wave that as it dissipates becomes an acoustic wave we hear as thunder. Photo: © James "Bo" Insogna