Ben2 From , joined Dec 1969, posts, RR:
Reply 1, posted (14 years 3 days 11 hours ago) and read 942 times:
It depends on the icing. Generally, severe icing not associated with severe thunderstorms will be given a SIGMET advisory. When the icing is moderate, an AIRMET is issued. AIRMETS are less severe than SIGMETS, and convective SIGMETS are issued when adverse conditions are present due to severe thunderstorms. Hope this helps.