Winds moving in a cloud creates two ions, positive and negative. The positive ions are pushed to the top of the cloud. The negative ions are pushed to the bottom of the cloud. The top of the cloud becomes the anode and the bottom of the cloud becomes the cathode. The air in the middle of the cloud becomes the insulator. The cloud is now a battery or the equivalent of a charged capacitor.

The negative ions on the bottom of the cloud causes the ground and air below to ionize causing them to become positively charged. The positive ions of the ground pull electrons out of the air, forming a positive ion path. The negative ions below the cloud repel electrons in the air and attract the positive ions, leaving behind a pool of electrons, forming a negatively charged path. The ionization occurs like cracks in a wall. The cracks appear as streams which can be seen when your hair stands on end. These ionized paths grow from the bottom of the cloud to the ground and from the ground to the cloud. Since the charge in the cloud is greater than the charge on the ground, the paths from the cloud to the ground grow faster than the paths from the ground to the cloud. The path that ionization takes depends on the strength of the air at any given point and usually results in an ionization path splitting, producing forks . Eventually one or more ionized paths from the cloud will connect with one of the ionized paths from the ground. The first fork to make a connection to the ground discharges, followed by electrons in the next nearest upper fork on the path. This process continues all the way back up to the cloud.