Glatteis

Glatteis, or black ice, is a thin, transparent layer of ice that forms on roads, pavements, and other surfaces when moisture freezes. It can be nearly invisible against dark asphalt, making it a common cause of slips and vehicle skids in winter. The term Glatteis is used in German-speaking regions to describe this hazard.

Formation occurs when temperatures fall below 0°C and water from rain, melted snow, dew, or humidity freezes on contact. Frost on existing ice may also thicken into a smoother, harder sheet. Surfaces that stay moist or are shaded or elevated (bridges, overpasses) are particularly prone to Glatteis.

Identification and hazards: Glatteis often appears as a glossy, glassy surface and can be hard to detect, especially in low light or at dawn. It reduces friction, increasing the risk of slipping for pedestrians and skidding for vehicles. The danger is heightened on curved or shaded sections and during wet or misty conditions.

Prevention and safety: Road authorities may treat surfaces with salt, grit, or other de-icing agents to lower the freezing point and improve traction. Individuals should wear appropriate footwear, use winter tires where available, and drive with reduced speed, increased following distance, and smooth steering and braking. Pedestrians should take careful, flat steps and avoid uneven areas.

Glatteis is a general term for ice hazards produced by freezing moisture and is closely related to the concept of black ice in other languages. It poses recurring safety challenges in regions with freezing temperatures and moisture levels.