Skyformationer

Skyformationer is a term found in several Nordic languages used to describe notable patterns or structures visible in the sky. It covers a broad category of phenomena, including clouds, light effects, and color changes caused by atmospheric conditions, rather than a single, discrete event.

Common skyformationer include lenticular clouds formed by airflow over mountains and other organized cloud shapes such as wave clouds and cirrus veils. Atmospheric optics create halos, sundogs (parhelia), ice-crystal halos, glories, and rainbow arches when sunlight or moonlight interacts with cloud particles. Other phenomena sometimes classified as skyformationer are noctilucent clouds and auroras, as well as crepuscular rays that illuminate the sky.

Formation mechanisms involve moisture content, temperature profiles, humidity, and wind. Orographic lift, temperature inversions, and wind shear foster structured cloud formations, while diffraction, refraction, and reflection of light by ice crystals or droplets produce optical effects. Local geography and seasonal variations influence which skyformationer are most likely to appear at a given time.

Observation and significance: skyformationer are noted worldwide under suitable atmospheric conditions and can be of interest to meteorologists, pilots, photographers, and skywatchers. While the term is not a formal meteorological category in English, it serves as an umbrella for discussing the range of sky patterns. Related concepts include cloud types, atmospheric optics, halos, and aurora phenomena.