Baikal ice is a rather interesting phenomenon. Its transparency is striking: it seems that you are walking on a huge mirror. Its diversity impresses a lot: the lake represents a variety of types of ice: from usual ice hummocks to peculiar ice hills.
So what is Baikal ice like?
One of the first features of the Baikal ice is the late freezing of the lake which can be explained.
It seems that winter has come, the temperature has dropped below zero degrees Celsius (which is known to be the ice point), the coast is covered with snow, but Baikal still does not freeze. The ice on the lake usually freezes in the first or even second half of January, that is, only in the middle of winter.
The cooling of water reservoirs, as a rule, begins in autumn with the onset of cold weather, when the water surface loses its heat, contacting with cold air. The process itself undergoes three stages. The first one begins in autumn from a decrease in the temperature of the surface layer of water. When it drops to 4 ° C, the second stage begins: during this stage the heavier upper layer of water starts to slide down, and its former place is occupied by warmer and lighter water layers rising from the depth. This goes on until all the water layers (cold and warm) are evenly “mixed”, their temperature dropping to the same temperature of greatest density. Then it’s time for the third stage: the surface layers are cooled without going down until their temperature drops to 0 ° C. This is when ice on the lake begins to freeze.
These three standard stages of freezing of water reservoirs obviously prove: the deeper the lake is (that is, the thicker the layer of water participating in annual heating and cooling is), the longer period of time is needed for the ice to freeze. Needles to say, Baikal is once again “ahead of the curve” in this issue.
The famous Baikal researcher, a Soviet geophysicist, the Director of the Irkutsk Magnetic and Meteorological Observatory, a Professor of the Irkutsk State University V.B. Shostakovich wrote the following lines in his well-known work dated by 1908 and dedicated to the Baikal ice:
“By approximate calculationd, it turns out that the volume of the mass of Baikal water undergoing annual cooling amounts to 3000 cubic versts (thousands of billions of cubic meters). This huge figure to some extent explains the slow cooling of the lake. A significant thickness of water under the above-mentioned 200-meter layer has a constant temperature of about 4 ° C. This heat reserve, despite the insignificant thermal conductivity of the water, cannot but influences the surface layers and slows down their cooling.
Anyway, by the end of December the temperature of the surface layer of the lake water approaches to 0 ° C, and if the entire lake is covered by ice only in the first half of January (N.S.), this depends mainly on the fact that the constant storms on Baikal in late autumn hinder the formation of an unbroken ice cover.”
Baikal is freezing gradually. First, the surface of the water is covered with a thin crust of ice. However, Lake Baikal is a turbulent lake, so this thin ice crumbles and breaks into ice floes even upon insignificant waves, locals call these floes “salo” (“pork fat”). But the frost does its job, and border ice is formed along the coast: it is represented by narrow ice strips near the coast which freeze as the waves wash the coast. During the storms, ice crusts grow and icicles-stalactites hang on the rocks, the reason being the water splashes that freeze. A peculiarity of Lake Baikal is accumulated ice; this type of ice clumps is called “sokui”.
“Sokui” water appear in shallow waters: the water near the coast cools down and freezes rather quickly, at the first frost. The waves splash and add water to the already frozen ice, the water freezes again and thickens the “sokui” and gives it a peculiar wavy appearance. “Sokui” ice clumps grow extremely fast during strong winds and snowstorms, due to the large mass of wet snow, being excellent construction material for “sokui” clumps. As a result, a more or less wide shaft consisting of opaque porous ice is often formed along the coast. Sometimes there are real ice grottoes in “sokui” clumps; but they disappear with the advent of spring.
You can often see ice formations characteristic exclusively of Lake Baikal, along the sokui clumps in shallow waters, in the breaker zone. These are called “hills”. They were first described by the scientists of the Baikal Limnological Station back in 1940s
The hills are regular, cone-shaped slides up to 6 meters high, hollow inside, formed of opaque porous ice. They are located separately or in groups, sometimes even in several rows, and resemble miniature mountain ranges. An interesting geographical feature of the hills is that they are common for the eastern coast, whereas you can hardly see any of them at the western coast.
Alongside with coastal “sokui” clumps and hills, a large numbers of floating ice floes are also found on Lake Baikal. Some of these are carried to Baikal by all the 336 rivers flowing into the lake during the autumn ice drift, some of them are formed from the remains of the “sokui” clumps, yet other floating ice floes are obtained from the bottom ice which is often formed around Bolshoye Goloustnoye and Mysovaya.
Floating ice is called “osenets”. It is usually opaque, whitish, with uneven surface. As a rule, “osenets” is considered to be the most enduring ice on Lake Baikal.
In addition to “osenets”, there is a type of ice called “kolobovnik” (or “myatik”). It consists of small rounded clumps of autumn ice bound together with smooth clear ice. Due to the insignificant thickness of these clumps, their surface becomes convex due to splashing waves.
The formation of bowl-shaped and disk ice also happens before the freezing of the lake, the way of its formation is similar to that of “kolobovnik”, the only difference being the fact that the separate clumps of the latter are much larger.
All these types of ice are very picturesque and beautiful: white rounded opaque spots of autumn ice are scattered all over the dark blue mirror ice.
Meanwhile, an invisible process of ice crystallization is underway in the open water. Water does not freeze right at once, because it is constantly “mixed” by waves. Nevertheless, due to a sufficient decrease in its temperature and optimum cooling of water, small lenses and needles (with their size as small as several millimeters) are formed in it.
Once the ice freezes, it begins to grow by about 4-5 centimeters per day. The shallowest bays are the first to freeze, the deep-water areas are the last. The Bay of Proval usually freezes in the first half of November, then the Maloe More Strait freezes at the beginning of December, the northern half of the lake and the Transbaikalian side of its southern part freeze by January, the eastern coast of the southern part of the lake freezes after that and, finally, mid-January is the time for ice freezing near the island of Olkhon. The average period of ice formation on Baikal lasts from January 9 to May 4. During this period of time the entire lake freezes. And only the source of the Angara (a section of the river 15-20 kilometers long) does not freeze at all.
Of course, Baikal has a classic of the “ice genre”, hummocks. They represent a chaotic accumulation of ice floes: some are sheer, others are inclined at different angles ... Their foundations are “moulded” into ice, and their tops are covered with snow. The height of hummocks ranges from several centimeters to a meter.
In general, the ice lasts for 4-4.5 months in the southern part of the lake, and up to six months in its northern part.
The newly formed thin ice begins to grow thick. At first the process goes quickly, but then slows down. The thickness of the ice usually depends on the severity of winter as well as on the amount of snow covering the ice, which can considerably tone down the effect of cold weather due to its low thermal conductivity.
Thickness of the ice throughout the entire water area of the lake ranges from 70 centimeters to 2 meters. Long-term observations show that the ice is thicker at the eastern coast.
Transparent snow-free ice is formed along the north-western coast and at the Maloe More Strait: you can see the bottom through such ice in shallow water.
The ice as thick as 50 cm can, as a rule, withstand a weight of up to 15 tons, that’s why they ride cars on the Baikal ice in winter. In 1904 an ice railway operated between the port of Baikal and the Tankhoy station at the eastern coast.
Local thawing of ice from below and the formation of so-called “vents” are observed in many regions of Lake Baikal in winter; the diameter of these vents can reach hundreds of meters. It is believed that the vents appear due to the effect of warm underwater springs. They are formed near the coast and present a serious danger, since the ice melts from below and becomes so fragile that it cannot endure even a light weight. At the beginning one or several small holes usually appear on the ice, but they rapidly increase and merge into one ice opening. The vents appear in the same places every year: at the capes of Kadilny, Goloustinsky and Goly, along the entire delta of Selenga, at the cape of Kobylya Golova and in the Maloe More Strait between Kobylya Golova and Sarma as well as near Ushkany islands, and in the lower part of the Svyatoi Nos Peninsula.
By the way, there is a version that the vents appear not because of underwater warm currents, but because some gas able to burn a bright flame accumulates under the ice. There is a famous old Baikal trick: if you make a hole in the ice with a quick blow and immediately bring a match to this hole, a fire will go out from the hole and burn until a large gas bubble under the ice is consumed.
Besides, satellite images of different parts of Lake Baikal were obatined in the spring of 2009: some dark rings were discovered on these. According to scientists, these rings emerge due to the rise of deep waters and an increase in the temperature of the surface water layer in the central part of the ring structure. As a result of this process, an anticyclonic (clockwise) flow is formed. Vertical water exchange speeds up in the area where the current reaches the maximum speed, which leads to an accelerated destruction of the ice cover.
Another feature of the Baikal ice is the cracks also known as “main cracks”. Under severe frost they literally break the ice into separate fields. The length of such cracks can amount to 10-30 kilometers, and their width - to 2-3 meters. Ice breaks occur annually, in about the same areas of the lake. They are accompanied by a loud cracking sound, reminiscent of thunder or gun shots. However, thanks to ice cracks, the fish in the lake do not die from the lack of oxygen. Oxygen is also produced by plankton algae rapidly developing under the transparent ice due to the penetration of sunlight.
The Baikal ice usually begins to break up at the end of April in the area from the Cape of Bolshoy Kadilny, under the influence of the ascending currents of warm water from underwater springs located at the bottom. In April the ice becomes more fragile, darker, and in May Baikal is mostly free from ice, although separate ice floes float on the lake water until early June. The northern part of the lake is the place where the ice melts in the end of the line (June 9-14)... Then another six months pass, and everything repeats once again.
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