ODD WEATHER, ODD ICE - Needle ice is a needle-shaped column of ice formed by groundwater. Needle ice forms when the temperature of the soil is above 32 °F and the surface temperature of the air is below 32 °F. Liquid water underground rises to the surface by capillary action, and then freezes and contributes to a growing needle-like ice column. The process usually occurs at night when the air temperature reaches its minimum.