Melting away: hotter climate set to make snow a lot less interesting

From crystalline columns to fern-like stars, snowflakes come in an assortment of shapes and patterns.

- Linda Geddes

The most intricate of all fall when the cold is so biting that only the most dedicated observer would linger to study them. But as temperatures warm, these ice crystals are likely to get a lot less interesting, the world's leading snowflake expert says.

Dr Kenneth G Libbrecht grew up in North Dakota, where snow is the main form of precipitation between November and March, but it was not until he moved to southern California that he began to study how snowflakes form. "I was interested in how crystals grow and form patterns, which led me into snowflakes because ice makes very interesting patterns as it grows," he said.

Experiments in the 1930s suggested different temperatures and humidities influence which crystals form: small plate-like structures at about -2C (28F), pencil-like columns and needles at -5C, and more intricate plates and stars at -15C. But the tests provided no explanation as to why.

So about 20 years ago, Libbrecht began growing his own snowflakes to systematically measure their growth under different conditions.