Interesting
Frost Flowers: The Rare Phenomenon That Blooms on Ice
Under just the right conditions, delicate white “flowers” can suddenly appear across newly formed ice. Here’s the fascinating science behind them.
- Tehila Cohen
- | Updated
Frost flowers usually form on thin, newly formed ice in extremely cold regions, particularly near the poles. They can also appear on frozen lakes, but when they form over seawater, they develop some especially fascinating properties.
How Do Frost Flowers Form?
The phenomenon occurs when a thin layer of new ice covers the water while the air above it is extremely cold. Water vapor near the surface of the ice changes directly from a gas into a solid, without first becoming liquid water.
The vapor settles on tiny irregularities in the ice and forms crystals. As more water vapor accumulates, the crystals grow and branch outward into delicate structures that resemble tiny white flowers.
For frost flowers to form, conditions need to be just right: young, thin ice, extremely cold air, sufficient humidity, and relatively light winds. Strong winds can damage the fragile crystals before they have a chance to fully develop.
Why Are Frost Flowers So Salty?
The ice crystals themselves form from water vapor, but frost flowers growing on sea ice come into contact with salty brine on the surface of the newly formed ice.
Their intricate, branching structure allows them to collect this brine. As a result, marine frost flowers can contain much higher concentrations of salt than the seawater beneath them.
Why Do They Disappear So Quickly?
Their striking appearance does not last long. Frost flowers are extremely fragile and may disappear within just a few days because of wind, snowfall, changing temperatures, or the thickening of the ice beneath them.
They may become buried under snow, break apart, or gradually sublimate back into the air. This is one reason frost flowers can be difficult to observe. They tend to appear in remote locations, under extreme conditions, and during a relatively brief window when the surface of the water is just beginning to freeze.
Although frost flowers may look almost alive, they are simply intricate ice formations. Interestingly, studies have found that marine frost flowers can contain microorganisms originating in the seawater and ice beneath them.
