Could a similar process be responsible for the high voltages that cause lightning in thunderstorms?
A thunderstorm cloud is essentially a violent upward flow of humid air. Rising air expands and cools, but the surrounding air at higher levels is cooler, too: what determines whether a flow continues to rise or not is whether it is warmer or cooler than the air around it. The rising flow in a thunderstorm gives up humidity in the form of rain (cooler air cannot hold as much water) and that process, it may be shown, provides extra heat. The water therefore keeps the air warmer than its surroundings, and it keeps rising. The result is motion in two directions: a wind blows upwards, and meanwhile raindrops fall through it towards the ground. Some raindrops are blown upwards by the wind, to higher levels where they freeze, and this too helps keep the air warmer. (Orange growers in Florida spray water when temperatures drop below freezing: the water freezes and falls to the ground, while orange trees are kept warmer.) Ultimately they may come down again as hail, commonly associated with thu
