The Science of Snowflakes

As the growing crystal drifts through clouds, it encounters varying temperatures and humidity levels, causing additional water vapor to freeze directly onto its surface. This interplay shapes the crystal into forms like simple plates, intricate stellar dendrites, or other familiar snowflake types. According to physicist Dr. Kenneth Libbrecht, snowflakes manifest in 35 distinct morphologies, shaped by three fundamental growth processes: faceting, branching, and sharpening. Faceting imposes geometric order, branching adds complexity, and sharpening refines the details.

A well-known study called the Nakaya diagram, shows how snowflakes change based on the conditions in the air. As it cools even more to -15°C, the classic snowflake shape begins to appear. Rarely, “split plates and stars” form when sudden changes in temperature disrupt the crystal’s growth, creating twin crystals attached at sharp angles. “Rimed snowflakes” form when crystals encounter supercooled water droplets, which freeze instantly upon contact with the crystal surface. These formations are important in avalanche forecasting, as fresh graupel layers often create unstable interfaces within the snowpack, increasing the risk of slides on steep terrain. While snowflakes’ six-fold patterns reflect the molecular geometry of ice crystals, perfect symmetry is rare. In reality, most snowflakes show subtle to significant differences across their six arms, making each one unique and charmingly imperfect.