Candle Ice

Thanks to its molecular makeup, water forms a hexagonal, crystalline structure when it becomes ice. Since ice is less dense than water, it floats. Not only is this great for drinks, but it also keeps large bodies from freezing from the bottom up. This attribute allows for a rather obvious but perhaps unpondered reverse reality: when systems heat, the last ice to remain on a body is typically at the surface.

Ice’s chemical bonds are not the strongest in the universe, but the highly ordered crystal is rather robust.

However, most people are likely aware of forms of ice that aren’t overly rigid. Think slush or brittle ice that crumples under human feet. When things start to warm or impurities creep into the crystals, ice can change from a solid that can take a pounding to a frangible mess.

When water exists in this state, we call it rotten ice.

Ice becomes rotten precisely because it loses its crystalline structure despite not having completely melted.

In the first photo above, the remaining rotten ice might support a few ducks but it’s definitely not going to hold a human ice skater. The second photo displays how ice in the sea can become rotten, too. Whether by increased temperature, the intrusion of salt into the structures, or a combination of the two, the ice is no longer solid solid.

Rotten ice is extraordinarily brittle and can pose massive safety hazards for people venturing onto lakes and oceans at the wrong time.

One specific formation of rotten ice, though weak, is quite striking.

Sometimes the transition from ice to rotten ice leaves cylinders perpendicular to the water surface. We call these structures candle ice, needle ice, or ice fingers.

To me, these formations resemble frozen versions of columnar jointing, the phenomenon that comprises Devils Tower and Giant’s Causeway. The difference, of course, being that those structures are hardy, while candle ice would crumble under the slightest perturbation.

The candles precipitate because minerals became trapped between crystals as the water originally cooled. When the process reverses, melting tends to start at these locations, which separate the ice into vertical columns thanks to the regularity of the crystals.

In addition to their visually pleasing arrangement, ice candles also produce wonderful music as they break apart. The ice opus takes the form of clinking, sometimes like dull wind chimes.

Candle ice tends to appear on lakes in the spring, as colder waters thaw.

Tread carefully when exploring this pleasing phenomenon. Though it can look solid, even taking up several feet of vertical space, it’s extremely volatile and cannot support the weight of humans!