Snowflakes can emit radio signals as they form and a better understanding of this process could provide a new way to monitor and study snow formation in the atmosphere. That’s the ice-cool conclusion of a group o’ physicists from France and Israel who have begun to tease apart some of the more subtle processes at work when snowflakes freeze.
Here’s what’s going on. In normal circumstances, the ions in water provide a convenient route through which water molecules can divest themselves of energy if they need to. But in de-ionised water, the molecules are perfectly insulated dipoles. So when they freeze into a crystal and become oriented in a specific non-random way, the only way their latent heat can be emitted is as radio signals.
It’s actually possible to pick up these low frequency signals of about 1000 Hz.
A new theoretical model built by Mark Perelman and pals from the Hebrew University in Jerusalem puts all this onto a sound footing for the first time and in a way that might mean that future weather forecasts will be based on data from radio transmitters tuning into the sound that snowflakes make as they form.
Ref: arxiv.org/abs/0712.2564: Freezing of Water and Crystals Formation: Double Electric Layer, Radio Emission, Dendrites, Snowflakes