St. Elmo's FireADDPMP120
St. Elmo’s fire is a weather phenomenon in which luminous plasma is created by a corona discharge from a sharp or pointed object in a strong electric field in the atmosphere (such as those generated by thunderstorms or created by a volcanic eruption).
St. Elmo’s fire is named after St. Erasmus of Formia (also called St. Elmo, one of the two Italian names for St. Erasmus, the other being St. Erasmo), the patron saint of sailors. The phenomenon sometimes appeared on ships at sea during thunderstorms and was regarded by sailors with religious awe for its glowing ball of light, accounting for the name. Sailors might have considered St. Elmo’s fire as a good omen (as a sign of the presence of their patron saint).
St. Elmo’s fire is a bright blue or violet glow, appearing like fire in some circumstances, from tall, sharply pointed structures such as masts, spires, and chimneys, and on aircraft wings or nose cones. St. Elmo’s fire can also appear on leaves and grass, and even at the tips of cattle horns. Often accompanying the glow is a distinct hissing or buzzing sound. It is sometimes confused with ball lightning. In the picture from the cockpit to the right, it is the background blue-violet glow and not the spark discharge across the cockpit window. St Elmo’s fire is akin to corona discharge from a negative electrode and not the spark, when the air finally breaks down and conducts.