When any one of these incidents occurs, circuit breakers or other protective equipment shut off the flow of power. All customers on that circuit lose power.
High winds are the most common source of outages.
Wind may cause two wires to slap together and short out. It may blow tree limbs or entire trees into or across lines, either knocking them down and breaking them, or knocking them into each other and causing a short. Mudslides may knock down poles, bringing the wires down with them and causing them to snap or slap together. Floods may inundate substations, forcing them to be shut down to prevent major damage to expensive transformers, capacitors, switches and other equipment. Wind may create such force against a pole and the equipment installed on it that the pole actually snaps in two, bringing the lines down with it.