Wikipedia
Needle ice is a phenomenon that occurs when the temperature of the soil is above and the surface temperature of the air is below . 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.
Alternate names for needle ice are " frost pillars" ("Säuleneis" in German), " frost column", "Kammeis" (a German term meaning "comb ice"), "Stängeleis" (another German term referring to the stem-like structures), "shimobashira" (霜柱, a Japanese term meaning frost pillars), or "pipkrake" (from Swedish pipa (tube) and krake (weak, fine), coined in 1907 by Henrik Hesselman).
The similar phenomena of frost flowers and hair ice can occur on living or dead plants, especially on wood.