Upslopesneeuw

Upslopesneeuw is a meteorological phenomenon describing snow that preferentially accumulates on the upslope or windward aspects of mountainous terrain. It results from orographic lifting: moist air is forced to rise when it encounters a mountain range, expands and cools, and can reach the dew point where precipitation forms, often manifesting as snow along the rising air column.

Formation and conditions: The effect depends on moisture content, air temperature, wind speed, slope steepness, and aspect. A persistent moist air stream provides a steady supply of water vapor; as the air ascends the slope, it cools adiabatically and can produce snowfall on the windward face. Depending on flow patterns, snow may accumulate up the slope as deposits, drifts, or layered structures. In maritime and other moist climates, upslope snow tends to be more pronounced during winter when air carries higher moisture content.

Implications: Upslope sneeuw can influence avalanche risk, as snow tends to accumulate in distinct layers on mountain slopes and in drifted deposits. It also affects ski tourism, road maintenance, and ecological conditions by shaping snow cover and insulation on different aspects. Forecasting and analysis rely on standard meteorological observations, radar and satellite data, and snowpack models to predict where snowfall will be concentrated and how stable the resulting snowpack may be.

See also: Orographic precipitation, Avalanche, Snowpack. Note: The term is a direct calque of the English phrase upslope snow; usage varies in Dutch meteorological literature.