Frost flower (sea ice)

The ice crystals are similar to hoar frost, and are commonly seen to grow in patches around 3–4 cm in diameter.

[1][2][3] Frost flowers form when a layer of relatively warm ice is exposed to still, cold air that is at least 15 °C colder.

The final result is a layer of supersaturated air, lying directly above the ice (just like how steam forms above the surface of a hot mug of water on a cold day).

Any protrusions from the ice surface stick up into the supersaturated air, and end up being covered in hoar-frost like crystals (i.e. frost flowers) due to condensation.

As ice thickens, its surface becomes much colder, and it is harder to get the necessary ice/air temperature difference needed for frost flower growth.

[4] Over fresh water, these conditions are only found when the air temperature drops dramatically below zero in a short amount of time, leading to a sudden freezing event.

[12] Frost flowers are complex in microstructural chemistry due to many different conditions, like air, temperature, chemical concentrations in the water, surface skim, humidity, and precipitation influencing their formation and growth.

When the salts begin the precipitate out of the ice, it changes the relative ion concentrations available in liquid water and in the frost flowers.

If the temperature were low enough for the sodium chloride that is present in the brine or frost flowers to freeze out, then the bromide may become readily available.