semisään

Semisään is a Finnish term that translates to "half-snow" or "half-ice." It describes a transitional state of precipitation where a mixture of rain and snow falls, or where snow is melting and refreezing. This phenomenon is most common during autumn and spring in Finland, when temperatures hover around freezing point.

The conditions that create semisään can lead to slippery and hazardous road conditions. As a mixture of rain and snow falls, it can accumulate on surfaces, and subsequent freezing can create a hard, icy layer. Even when the precipitation is not actively falling, a semisään situation can persist as melting snow refreezes, particularly during the night or in shaded areas.

Understanding semisään is important for weather forecasting and public safety in Finland. It signals a need for caution when traveling, especially for drivers and pedestrians. The visual appearance of semisään can vary, sometimes resembling wet snow, at other times a slushy mix, or even a thin layer of ice on top of existing snow. It represents a dynamic weather event where the boundaries between different forms of water are blurred.