When the landscape is covered with snow, we go skiing, enjoy the view or perhaps our car gets stuck in the snow. There are many of us who believe that snow is formed when a rain shower comes in contact with frost. But it’s not that simple. Bacteria in the atmosphere play a vital role.

“Water vapor needs something to settle on in order to be able to condense and turn into rain drops or snowflakes. This may be dust or soot particles in the atmosphere but more often than not, it is bacteria. Bacteria can be found everywhere in the atmosphere and are very good at absorbing moisture,” explains Sara Landvik, who works with Novozymes and is an expert in bacteria and other microorganisms.

Most bacteria in the atmosphere originate from plants and are completely harmless. Dust, soot and other non-biological particles cannot collect ice and water when the temperature is higher than minus 10 degrees, but bacteria can. They can actually form ice crystals even when the temperature is above freezing point. This means that bacteria can also be used to make artificial snow, such as the kind found on ski runs. Research has shown that a bacterium called Pseudomonas syringae is particularly good at forming snow.

Facts: What is a microorganism?
A microorganism is microscopic living organism. The study of microorganisms is called microbiology – a subject that began with Anton van Leeuwenhoek’s discovery of microorganisms back in 1674.

Microorganisms are very different and contain species of fungi, algae and certain animals, such as rotifers. Microorganisms can be found in all parts of the biosphere, e.g. in the soil, in hot springs, in the ocean and in the atmosphere.
Microorganisms are critical in ecosystems, as they help to sustain life and break down materials such as plants. Recent studies show that airborne microorganisms can play a role in precipitation and weather.
Microorganisms also play an important role in relation to cooking and producing, e.g. beer and wine, and are used in biotechnology, e.g. to make medicine and produce enzymes. Ref. https://en.wikipedia.org/wiki/Microorganism