Candle ice (sometimes known as needle ice) is a form of rotten ice that develops in columns perpendicular to the surface of a lake or other body of water. It makes a clinking sound when the "candles" are broken apart and floating in the water, bumping up against each other. As ice from a larger surface melts, the formation of candle ice "progressively increases with time, temperature, and quantity of water melt runoff. This occurs due to the hexagonal structure of the ice crystals; minerals such as salt, as well as other contaminants, can be trapped between the crystals when they initially form, and melting will begin at these boundaries due to the trapped contaminants.No matter the thickness, it can be dangerous due to its lack of horizontal structure, which means there will be no rim to grab for any person who falls through.