härmä

Härmä is a Finnish word that refers to frost, specifically the feathery ice crystals that form on surfaces when moist air comes into contact with a surface that is below freezing point. It is a type of deposition, where water vapor in the air turns directly into ice without first becoming liquid. This process occurs most commonly on cold, clear nights when there is little wind.

The appearance of härmä can vary greatly depending on atmospheric conditions. It can manifest as fine, powdery frost, or as more elaborate, needle-like or fern-like structures. The size and shape of the ice crystals are influenced by factors such as temperature, humidity, and the speed of the air. Härmä can form on a variety of surfaces, including plants, buildings, and vehicles.

In Finland, härmä is a common sight during the winter months and is often associated with the beauty of a frozen landscape. While it can contribute to slippery conditions, it is generally not considered a significant hazard in the same way that a heavy snowfall or ice storm might be. The term is also used in a more general sense to describe the feeling of coldness or chill in the air.