St. Elmo's Fire

A ghostly electric glow that appears on ship masts and airplane wings during storms/Weather & Climate

St. Elmo's fire is a luminous plasma discharge caused by the ionization of air in a strong electric field, typically during thunderstorms. It appears as a bright blue or violet glow emanating from pointed objects such as ship masts, church steeples, airplane wingtips, and even cattle horns. Named after St. Erasmus of Formia, the patron saint of sailors, it was considered a good omen by Mediterranean sailors for centuries. The phenomenon occurs when the electric field at a pointed conductor exceeds about 30,000 volts per meter, strong enough to ionize the surrounding air but not strong enough to produce a full lightning strike. It is not actually fire and is barely warm to the touch.