Needle ice

Needle ice pushing up soil particles

Packed needle ice

Needle ice is a phenomenon that occurs when the temperature of the soil is above 0 °C (32 °F) and the surface temperature of the air is below 0 °C (32 °F). The subterranean liquid water is brought to the surface via capillary action, where it freezes and contributes to a growing needle-like ice column.

The ice needles are typically a few centimetres long. While growing, they may lift or push away small soil particles. On sloped surfaces, needle ice may be a factor contributing to soil creep.^[1][2]

Alternate names for needle ice are "frost column", "kammeis" (the German term meaning "comb ice"), "shimo bashira" (霜柱 the Japanese term for "ice needles"), or "pipkrake" (from Swedish pipa (tube) and krake (weak, fine), coined in 1907 by Henrik Hesselman).^[3]

A similar phenomenon, "frost flowers", can occur on living or dead plants, especially on wood.

See also

• Frost heaving
• Frost

References

1. ^ Isbell, D.: Needle Ice on Mt. Osceola, EPOD of July 10, 2005. URL last accessed 2007-12-07.
2. ^ Pidwirny, M.: Fundamentals of Physical Geography, 2nd ed., section 10(ag), Periglacial Processes and Landforms. URL last accessed 2007-12-07.
3. ^ Lawler, D. M.: "Some observations on needle ice", Weather, vol. 44, pp. 406–409; 1989.

External links

Media related to Needle ice at Wikimedia Commons