As the temperature dips below freezing, some cloud droplets begin to freeze around dust particles in the sky and form hexagonal crystals. All snowflakes are six-sided because water molecules bond ...

More crystals grow on top of these ice crystals to create hexagonal shapes called snowflakes ... the heat from the sun melts the snow and this mixture of water and snow creates slush.

At sufficiently low temperature, liquid water crystallizes into ices with cubic or hexagonal symmetry ... dependence of water's homogeneous crystal-nucleation temperature.