'Freezing drizzle' is
drizzle that freezes on contact with the ground or an object at or near the surface. Its
METAR code is 'FZDZ'. When such drops land, it create an icy layer of glaze. Freezing drizzle alone does not generally result in significant
ice accumulations due to its light, low-intensity nature.
Formation
Drizzle is formed in low level
clouds, of the
stratus type, when vertical motion is weak. It consists of relatively small drops, light in nature. Freezing drizzle generally occurs when drizzle forms in an airmass at below freezing temperatures but warmer than -10
oC (12
oF). At such a temperature, the water droplets stay
supercool as there are few
ice nuclei to change them to
ice crystals. In winter arctic conditions, it can happen at even lower surface temperatures as the air is even cleaner.