How does needle ice form

This fragile structure of ice and dirt is what crumbled under my running shoes. Once these frosted soils melt, they are loose and susceptible to erosion.

If the needle ice forms on a slope, even just the action of lifting soil particles up and letting them down again will cause them to descend in the process of soil creep. Only certain soils are frost-susceptible, though. Very dense, clay soils do not promote water flow, and clean sand is too well-drained.

The ratio between pore size the space between the grains and particle surface area must be within a range that promotes capillary action. This is the ability of the water to flow through narrow spaces without the help of gravity, and often against it. When the nurse pricks your finger and captures your blood in the tiny tube, it is capillary action that causes the flow. Silty and loamy soils—with particle sizes in between clay and sand—tend to be the most frost-susceptible.

When I replace the sand with heavier soil that has a high clay content, the same setup grows needle ice from the soil that pushes the pebbles upward. Curious observers from around the world have sent me photographs of spectacular spirals and ribbons of ice that have naturally extruded from metal pipes in various locations as shown at right, top and bottom left. Ice occupies about nine percent more volume than water, so with freezing there will be expansion.

My first attempt at deliberately reproducing this phenomenon used plastic pipes that were on hand, but they soon shattered.

However, black iron pipes are sometimes able to withstand the pressure. Photograph at top courtesy of Sheryl Terris.

Photograph at bottom left courtesy of Raul Baz. Photograph at bottom right courtesy of the author. My tests showed that one end of the pipe must be flattened, or capped and cut with a small hole or slit, to force the ice out in dynamic shapes. I then fill the rest of the pipe with chilled water but not supercooled water, or it will freeze on contact and cap the other end.

I flip the pipe upright, so the slit and ice plug is at the top, and set it outside on a freezing night. With luck, as the chilled water in the pipe expands, it will force the plug of ice out the narrowed end or slit and create long curls as shown above on bottom right. These experiments suggest that natural ice ribbons from pipes and fences develop over two or more days.

On the first night when temperatures drop below 0 degrees Celsius, water in the pipe freezes. The next day, some ice melts while the remainder floats to the top, creating a plug of ice.

When temperatures drop again the next night, the water chills and expands, pushing the ice plug out of any available holes. I wonder how many other dramatic examples of ice extrusions have never been seen because they have appeared in out the way places on cold mornings. Skip to main content. Login Register. Flowers and Ribbons of Ice By James Richard Carter Beautiful, gravity-defying structures can form when water freezes under the right conditions. Page DOI: Photograph courtesy of the author..

Photographs courtesy of the author. Photograph courtesy of the author. Bibliography Lawler, D. A bibliography of needle ice. Cold Regions Science and Technology — Wagner, G. Preuss and D. Enlightening the mystery of hair ice. Blossoms of ice. Natural History — Meentemeyer, V. Soil moisture and texture controls of selected parameters of needle ice growth. Earth Surface Processes and Landforms 6: — Outcalt, S. Needle ice formed in this manner is normally about an inch long, but it can grow to as long as a foot under ideal circumstances.

Experimentation in laboratories has confirmed the underlying physical properties that engender needle ice. It was concluded that the experimental process replicated the formation of needle ice in loose soils. The formation of needle ice structures is a well-recognized phenomenon in areas with the necessary and sufficient environmental conditions; it is called kammeis in Germany, pipkrake in Sweden and shimobashira in Japan. It occurs on sloped regions to the extent that a special name ,kammeissolifluktion, is given to the process of movement of soil down the face of a slope due to comb ice.

The Swedish name pipkrake is used largely in reference to sub-arctic needle ice. Pipkrake formation results in frost creep, one of the primary geomorphologic processes associated with the shift of temperature across the freezing point of water. Frost creep occurs in permafrost regions due to the action of the individual pipkraken needles that rise beneath individual sediment particles.

The formation of ice structures that resemble flowers or ribbons is due to a freezing phenomenon that is closely related to that which causes needle ice. While the process is simple enough, the resulting delicate "hair" growing up from the ground is something rather amazing to look at. Yet another version of frost flowers can be found floating on the surface of newly frozen sea ice or lake ice. Also called frost blossoms or Arctic blossoms, these little ice formations are quite interesting to scientists.

In , a biology team from University of Washington was sailing near the North Pole when they found a vast field of these little ice blossoms. When they melted a few, they found that they hold an unusually large amount of bacteria. First, let's cover how they form. Here's how NPR explains it: "[T]he air was extremely cold and extremely dry, colder than the ocean surface.

When the air gets that different from the sea, the dryness pulls moisture off little bumps in the ice, bits of ice vaporize, the air gets humid — but only for a while.

The cold makes water vapor heavy. The air wants to release that excess weight, so crystal by crystal, air turns back into ice, creating delicate, feathery tendrils that reach sometimes two, three inches high, like giant snowflakes. The sea, literally, blossoms. Now here's why they're scientifically fascinating: We mentioned that these frost flowers contain a surprising amount of bacteria.

Because of the way they form, frost flowers have three times the salinity of the ocean, and not much could live in such salty frozen water. Or so we think. But the researchers found about a million bacteria living in each frost flower.

More research could reveal just what the bacteria are up to in those blossoms and how they manage to survive. They look a lot like baled hay made of snow.

And in a way, that's a pretty accurate description. In a similar way to how hay is rolled up into large balls, a snow roller is formed as a chunk of snow is blown along the ground by the wind, picking up more snow as it rolls and growing in size. They are cylindrical, and usually hollow since the first few layers to form usually flake away pretty easily as the rollers get, well, rolling.

They can get as big as two feet in diameter. Snow rollers usually happen when there is a fresh layer of loose snow on the ground and the temperature is near melting.