flakesim

Grow a snow crystal from the environment it falls through — Libbrecht's attachment kinetics on a three-dimensional vapour field, running here in WebAssembly. Pick a history, press Grow, and watch.

History file (editable)

The [simulation] radius, cell size and growth model above override the file's when you press Grow. Keyframes are [[history]] tables with time (s), temperature (°C) and supersaturation (g/m³ over ice) or humidity (% over water); pressure (hPa) is optional.

Ready.
From above
Relief view

The morphology diagram, grown

Forty-eight crystals grown for ten minutes each under constant conditions (0.5 µm cells, 300 µm across), laid out like the Nakaya diagram: warm on the left, humid on top. Each cell shows the crystal from above and in relief. These are pre-rendered — the full chart takes a couple of hours on a 64-core machine.

Poisson model

Morphology chart, Poisson growth model

Quantised model

Morphology chart, quantised growth model