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Crown snow-load is snow and hard rime accumulating on tree crowns and structures in a cold climate. Hard rime is formed when droplets of fog or low level cloud (Stratus) freezes to the windward (wind-facing) side of tree branches, buildings, or any other solid objects, usually with high wind velocities and air temperatures between -2 °C (28 °F) and -8 °C (18 °F). Especially when a warm front brings wet snow, the surface of the tree is colder than the snowflakes, and the latter attach to the tree crown.
In Scandinavia, largest snow-loads accumulate to the trees on top of medium-sized fells. The larger fells and mountains have no trees, and the tops of lowest fells do not reach the cloud bases so often. Also the wind speeds are largest on fell tops. One spruce in Northern Finland can collect 3-4 tonnes of snow. When the crown is loaded with snow, a storm can easily damage the trees. Snow-loaded trees also pose a risk to powerlines.