Hard rime

Rime ice is a solid precipitate that forms, especially at high wind speeds and an air temperature of typically from -2 to -10 ° C from supercooled water droplets or mist spray on surfaces, typically opposite to the wind direction. The resulting ice layer of gray - white granular particles has a sponge-like appearance and is compared to a solid clear ice quite loose.

Rime is characterized in that it has no crystalline structure and includes a large number of air bubbles in its structure. The partial melting and refreezing of the particles cause them to stick together different greatly, depending on the prevailing temperature conditions. Rime ice can therefore reach a certain strength, it loses some degrees Celsius but quickly and then by falling ice cubes easily become a danger to passers-by.

Rime ice deposits, as well as clear ice, preferably on branches and power lines, where it can be especially as Anraum, by the additional weight load sometimes not inconsiderable damage. Both phenomena are to be distinguished from frozen dew, frost and hoarfrost.

Rime in aviation

Compared to crystal ice rime is of lesser danger for flight safety, but also not to be underestimated. Recognizable it is - in contrast to clear ice, which back to the wings "grows" - its fine ( as described above ) structure which grows against the direction of flow.