Kontojääk

Kontojääk is a Finnish term that translates to "squirrel ice" or "chipmunk ice." It refers to a type of ice formation that appears on bodies of water, such as lakes and rivers, during the late autumn and early winter months. This ice is characterized by its rough, uneven surface, often dotted with small, upward-pointing spikes or mounds. These formations resemble the texture of a squirrel's fur or the back of a chipmunk, hence the name.

The formation of kontojääk is typically attributed to a combination of factors. Cold temperatures cause a thin layer of ice to form on the water's surface. If the water then experiences slight movement, such as from wind or currents, this initial ice layer can break and refreeze in a fragmented, bumpy pattern. Another contributing factor can be the presence of submerged vegetation or debris, which can disrupt the smooth freezing process and create these irregular shapes.

Kontojääk is generally not thick enough for safe travel across it. Its appearance signals the transition from open water to more stable ice conditions. While it can be visually striking, it is primarily an indicator of the changing season and the initial stages of winter ice formation. The term is part of the vernacular used by people living in regions with cold winters, particularly in Finland, where observing and understanding ice formations is a practical skill.