Melting or otherwise disintegrating ice on open water
Rotten ice is a loose term for ice that is melting or structurally disintegrating due to being honeycombed by liquid water, air, or contaminants trapped between the initial growth of ice crystals. It may appear transparent or splotchy grey, and it is generally found after spring or summer thaws, presenting a danger to those traveling or spending time in outdoor recreation. The increase of rotten ice vs. solid ice in the Arctic affects ocean-atmosphere heat transfer and year-to-year ice formation, as well as the lives of the Inuit, sea mammals such as walrus and polar bear, and the microorganisms that live inside the ice.
Rotten ice has a subtype called \"candle ice\", which has a columnar structure. Like other rotten ice, it poses a hazard to humans due to its lack of structure.
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.