A fall of non-branched (snow crystals are branched) ice crystals in the form of needles, columns, or plates.
unbranched ice crystals that fall as needles or plates. They only occur at cold temperatures (lower than -20 C) and can fall from a cloudless sky.
A barely visible crystalline form of ice that has the shape of needles, columns or plates. Ice crystals are so small that they seem to be suspended in air. Ice crystals occur at very low temperatures in a stable atmosphere.
A type of precipitation composed of unbranched crystals in the form of needles, columns, or plates. Usually has a very slight downward motion and may fall from a cloudless sky.
Tiny particles of ice that grow on all surfaces when the air is supersaturated with water (cold air doesn't hold much moisture so ice crystals are readily formed in Antarctica). Ice crystals account for the majority of the accumulation of glacial ice on the Polar Plateau. They may also be referred to as ice needles, even though they are not needle shaped. Freshwater.
Precipitation in the form of slowly falling, singular or unbranched ice needles, columns, or plates. They make up cirriform clouds, frost, and ice fog. Also, they produce optical phenomena such as halos, coronas, and sun pillars. May be called "diamond dust." It is reported as "IC" in an observation and on the METAR.