Hydro-Québec measures the impact of sound produced by its power transmission lines and other equipment.

This phenomenon, called the corona effect, intensifies when impurities fall on the wires and when the air is very humid. The crackling sound is loudest when it snows or rains. Electrons moving between the wires and the air cause the corona effect. This back-and-forth movement creates a multitude of tiny electrical discharges, which we perceive as a crackling sound. The higher the voltage, the greater the chance this phenomenon will occur.