snødannelse

Snødannelse refers to the process by which snow crystals form in the atmosphere. It begins when water vapor in clouds reaches a very low temperature, below freezing, without necessarily turning into liquid water first. This process is called deposition.

In the presence of microscopic particles, such as dust or pollen, known as ice nuclei, water vapor can directly transform into ice crystals. These initial ice crystals are typically hexagonal in shape due to the molecular structure of water.

As these ice crystals grow, they fall through the cloud. If they encounter more water vapor, they can continue to grow through accretion, where water vapor freezes onto the existing crystal. The specific temperature and humidity conditions encountered during their descent influence the growth pattern of the ice crystals, leading to their diverse and intricate shapes, such as dendrites (star-like shapes), columns, or plates.

When these ice crystals become heavy enough, they fall to the ground as snow. The accumulation of these crystals forms a snowpack. The process of snødannelse is a crucial part of the Earth's water cycle and plays a significant role in weather patterns and climate. Different atmospheric conditions result in different types of snowflakes, impacting their texture and how they behave when they reach the surface.