Wx Aviation

World Wide Radar List

US Icing

USA Icing Probability 5000 FT to 23000 FT
Current Analysis to 18 hour forecast

5000ft | 00hr | 01hr | 02hr | 03hr | 06hr | 09hr | 12hr | 15hr | 18hr | --- 7000ft | 00hr | 01hr | 02hr | 03hr | 06hr | 09hr | 12hr | 15hr | 18hr |

9000ft | 00hr | 01hr | 02hr | 03hr | 06hr | 09hr | 12hr | 15hr | 18hr | --- 11000ft | 00hr | 01hr | 02hr | 03hr | 06hr | 09hr | 12hr | 15hr | 18hr |

13000ft | 00hr | 01hr | 02hr | 03hr | 06hr | 09hr | 12hr | 15hr | 18hr | --- 15000ft | 00hr | 01hr | 02hr | 03hr | 06hr | 09hr | 12hr | 15hr | 18hr |

17000ft | 00hr | 01hr | 02hr | 03hr | 06hr | 09hr | 12hr | 15hr | 18hr | --- 19000ft | 00hr | 01hr | 02hr | 03hr | 06hr | 09hr | 12hr | 15hr | 18hr |

21000ft | 00hr | 01hr | 02hr | 03hr | 06hr | 09hr | 12hr | 15hr | 18hr | --- 23000ft | 00hr | 01hr | 02hr | 03hr | 06hr | 09hr | 12hr | 15hr | 18hr |

Outside Air Temp. Range Icing Type
   2 ° C to -10° C     Clear
-10° C to -15° C     Mixed
-15° C to -20° C     Rime
Most icing tends to occur at temperatures between 0°and -20°C
*More than 50% of those occur between -8 and -12°C




USA Max Icing Serverity   

00H Analysis to 18H forecast FL010-FL300


imageloop
Clear ice typically forms when temperatures are around 2 ° C. to -10° C. and with the presence of large water droplets freezing drizzle, or freezing rain.  Clear ice is the most dangerous type of structural ice not only because it is hard to see, but also because it can change the shape of the airfoil.  In addition, clear ice often forms well beyond the ice-protected areas of the aircraft.

Mixed ice, a combination of clear ice and rime ice that has the worst characteristics of both, can form rapidly when ice particles become embedded in clear ice and build a very rough accumulation. 


Mixed ice is most likely to form at temperatures between -10° C to -15° C. 

Rime ice forms when small droplets freeze immediately on contact with the aircraft surface.  It typically occurs with temperatures between -15° C. and -20 ° C.  Rime ice has a milky, opaque appearance resulting from air trapped when it strikes the leading edge of an airfoil and freezes.   It is less dense, and usually easier to remove than clear ice. 
Rime ice tends to form wedge-shaped accretions that do not disturb airflow as much as clear ice.