(this article is first published in the fruit shell)

this article will take you to enjoy six peculiar ice and snow phenomena.

(James R. Carter)

this is not an ice flower on the window, but a kind of slender ice crystal growing vertically from the base of plant stem, which is often called "Ice Flower" in English. This phenomenon is usually found on cold winter mornings.

according to observation and speculation, it should be formed like this: "Binghua" usually grows on some cold winter nights, when the temperature is very low, but the soil is relatively warm and has not yet frozen. The stems of these plants may be dead this season, but there are still pipes inside them that absorb water. Ice is larger than water and expands outward when it freezes, while the pipes inside the plant can also rely on capillarity to transport unfrozen water from the soil, come into contact with cold air, and continue to freeze. As a result, the slender ice crystal structure is gradually extruded from the plant stem. The "growth" pattern perpendicular to the stem suggests that these ice flowers should grow from the plant's lateral transport pipe.

(dynamic picture: the growth process of ice flowers)

because they are very slender, these "ice flowers" are easy to melt when heating up during the day, so they can only be seen in the early morning.

Ice spike

(an ice nail frozen in the outdoor environment)

"ice nail" (ice nail) can be observed in outdoor frozen pools and refrigerator ice compartments, so this is a phenomenon that can also be seen in summer. When the water in these containers freezes, sometimes a slender icicle protruding grows upward, and this is the ice nail.

the formation of ice nails can be understood as follows: in a container, water first freezes from the outer layer, and at the same time, the volume of ice expands and squeezes the remaining water. On the frozen surface, there may be a relatively weak hole somewhere, so as the frozen ice expands, the remaining liquid water will be squeezed out of the hole and frozen on the outside of the extruded part to form an upward tube. Then the remaining liquid water continues to be squeezed out and frozen, eventually forming an upward growth "ice nail". These structures are generally slender and pointed upward, and the location and direction of occurrence are relatively random.

(Bally-Dorsey model that explains the formation of ice nails)

how to make ice nails in the refrigerator? In 2003, a paper discussed the conditions for the formation of ice nails [1]. They concluded that ice nails were most likely to occur under the conditions of about-7 ℃ and high water purity. In addition, "frost-free refrigerators" that prevent frost through air circulation are also more likely to produce ice nails than still air.

Bubble Ice

(frozen bubbles in Lake Baikal | Kristina Makeeva)

frozen lake ice sometimes seals a string of bubbles. What's in these bubbles? The answer is methane. They are mainly produced by the decomposition of organic matter by microorganisms at the bottom of the lake. In winter, these methane bubbles are blocked by ice and eventually frozen. It is said that this phenomenon mainly occurs in the thermokarst lake in the permafrost region.

if the ice shell is melted, the methane in the bubble can also be ignited (but please do not imitate).

Ice turntable

(Tina Radel/City of Westbrook)

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Snow Roll

Perduejn/Wikipedia

to form a snowroll, you need wind of the right intensity, as well as loose and moist snow on the surface, preferably near the melting point of the ice. The surface snow should be able to stick to the rolling snow roll, and at the same time it should be easily separated from the underlying snow. The wind speed of about 13 meters per second is suitable for rolling snow rolls without blowing them apart, or snow rolls can also roll under gravity along the hillside.

Snow thorns stand

(Arvaki/Wikipedia)

the originally flat snow cover sometimes turns into rows of ice and snow "spikes", which can be 1-4 meters high. This phenomenon is called "penitentes" (Spanish for confessor, because it looks like a lot of people are confessing), and what we see above is the penitentes phenomenon in the Andes in central Argentina, and these "spikes" are more common in the high elevations of South America.

the formation of ice and snow "spikes" requires strong light, as well as a dry and cold environment, in which light should play the most important role. The snow looks smooth at first, but there are a lot of things on it.There are small holes in the machine, where the sun may not reflect away directly, but will be reflected many times in the pit. As the number of reflections increases, the part absorbs more energy from the sun, which makes the ice and snow at the bottom of the small depression more likely to sublimate and melt. As a result, the depression becomes deeper and deeper, eventually turning the flat snow into rows of spikes.

references:

1. Http://www.its.caltech.edu/~atomic/snowcrystals/icespikes/icespikes.pdf

2.https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.96.098502