glaze

Glaze is a smooth clear coat of ice laid over every surface by freezing rain, when raindrops fall through a layer of below-freezing air near the ground and freeze on contact. It is dense, heavy, and transparent, unlike rime, which is opaque and builds from fog. Half an inch of glaze on a branch can multiply its weight several times, which is why an ice storm takes down limbs and lines that a heavy snow would not.