Hard rime

From Glossary of Meteorology

hard rime

Opaque, granular masses of rime deposited chiefly on vertical surfaces by a dense supercooled fog.

Hard rime is more compact and amorphous than soft rime and may build out into the wind as glazed cones or ice feathers. The icing of ships and shoreline structures by supercooled spray from the sea usually has the characteristics of hard rime.