Crown snow-load

Hard rime is formed when subcooled droplets of fog or low-level stratus cloud freeze on the windward (wind-facing) side of tree branches, buildings, or any other solid objects.

This takes place usually with moderate wind speeds from 3 to 6 m/s (9.8 to 19.7 ft/s) and air temperatures between −2 and −8 °C (28 and 18 °F).

Snow may accumulate directly on the trees when a warm front brings wet snow, the air temperature is slightly above the freezing point and the surface of the tree is colder due to a preceding cold spell.

[1] In Scandinavia, largest snow-loads accumulate to the trees on top of medium-sized fells.

When the crown is loaded with snow, a storm can easily damage the trees.