Candle ice is a temporary yet striking formation that appears as winter transitions into warmer seasons. Understanding how these formations develop offers insight into the complex processes of ice melt and the changing states of water in natural environments.
What is Candle Ice?
Candle ice earns its name from its distinctive appearance, resembling numerous long, vertical columns. These ice structures often stand upright in water or float loosely. Also known as “needle ice” or “rotten ice,” it maintains a columnar form perpendicular to the water’s surface. When disturbed, these individual ice columns can produce a subtle clinking sound.
The Science Behind Its Formation
The formation of candle ice is a process of decay rather than initial freezing, occurring as an existing ice sheet begins to melt. Ice is a polycrystalline material composed of many individual ice crystals, or grains. The boundaries between these crystals, known as grain boundaries, are weaker and contain impurities or disordered ice that melts at a lower temperature than the main crystal structure.
As solar radiation penetrates the ice, it preferentially targets and melts these less stable grain boundaries. This targeted melting creates vertical channels or “honeycombs” within the ice sheet. Meltwater then seeps into these channels, accelerating the weakening and separation of the ice along these boundaries. The result is the characteristic columnar shape, where the stronger parts of the ice crystals remain. This process is particularly pronounced as ice thins and warms, allowing sunlight to penetrate more effectively.
Where and When Candle Ice Forms
Candle ice typically forms during late winter and early spring. It requires increasing sunlight and rising temperatures to initiate the melting process. This phenomenon is most commonly observed in fresh water bodies such as lakes, ponds, and slow-moving rivers. Areas with very cold winters, such as Canada, Alaska, and Lake Baikal in Russia, frequently experience candle ice formation.
Implications and Safety
Despite its visually appealing nature, candle ice signifies a significantly weakened and unstable ice cover. It is considered “rotten ice” due to its compromised structural integrity. The lack of horizontal structure means it cannot support weight, making it exceptionally dangerous for any activity on the ice, including walking or driving. This weakened state contributes to the rapid breakup of ice sheets, posing a hazard to people and wildlife.