Information regarding freezing precipitation can be found in the METAR or TAF. Don’t be
tricked into complacency by reported rain or drizzle at near freezing temperatures, as
this, too could stick to your aircraft.
Freezing Fog (FZFG)
Contact between freezing fog and the surface of your aircraft can be enough to phase
change the super-cooled water droplets to ice, that adheres to the aircraft surfaces.
Taxiing through freezing fog can result in ice formation inside the engine inlet and
possibly on the fan blades.
Snow (SN)
Snow, snow grains (SG) and snow pellets (GS) are readily forecasted. Depending on the
moisture content of the snow and temperature/condition of your aircraft skin, it may or
may not stick to the aircraft. To anticipate the go/delay/no-go decision, or which anti-icing
fluid to use, you need to know the snowfall intensity.
Freezing Rain (FZRA) & Freezing Drizzle (FZDZ)
Both freezing rain and freezing drizzle are forecasted, but also watch for rain or drizzle at
near freezing temperatures. These forms of freezing precipitation are particularly
hazardous both on the ground and in the air. Besides leaving a layer of ice that can be
difficult to remove, and a challenge to protect against (with anti-icing fluids), in-flight ice
protection systems may not be able to adequately protect against freezing rain or drizzle.