Ellen Phiddian
Cosmos science journalist
The motion of falling snowflakes can be used to help predict precipitation, according to a new study.
The research, which modelled 3D-printed ice crystals falling in glycerine, could be used to improve weather and cloud predictions.
The study is published in Atmospheric Chemistry and Physics.
Modelled falling snowflakes. Credit: Stout et al., 2024, Atmospheric Chemistry and Physics, doi.org/10.5194/acp-24-11133-2024
“Watching snow gently falling can be mesmerising, so it has been a joy to uncover the ways in which different ice crystal shapes pirouette and zigzag on their downwards journey,” says lead author Jennifer Stout, a PhD candidate in meteorology at the University of Reading, UK.
“Understanding the dance of a snowflake is not only beautiful but can help us understand the reflectivity of clouds. Each snow crystal in a cloud acts like a tiny mirror, reflecting and refracting the light that passes through it.
“By predicting the choreography of an entire cloud, we could better improve our understanding of the atmosphere and the processes which lead to rain and snow.
“This intricate coordination of snowflakes can also create a big visual impact, causing stunning phenomena such as sun dogs and ice halos.”
The researchers 3D-printed a variety of different snowflake shapes, ranging in complexity from simple circles to branched dendrites.
They dropped these models into a tank filled with a mixture of water and glycerine, filming their movement with 3 high-speed cameras.
This revealed 4 different falling patterns: stable (straight down), zigzag (swinging), transitional (zigzagging and spinning), and spiralling (spinning).
More complex snowflake shapes had more stable fall patterns than the simple ice crystal shapes.
The spiralling motion in the tank. Credit: Stout et al., 2024, Atmospheric Chemistry and Physics, doi.org/10.5194/acp-24-11133-2024
This revealed new information about the angles at which these snowflakes fell.
Because weather radar rely on the angles of ice crystals in clouds, the researchers say that incorporating this information could help to make weather forecasts more accurate.
