When one beautiful winter frosty day fog spreads over the still unfrozen river, and ice floes and clods of sludge calmly float downstream, suddenly the water level begins to rise due to the thickening ice drift - residents of coastal areas know that it is time for a glut. What is characteristic of this phenomenon and how to get out of it?
Description of the phenomenon
From the start of the zazhor, the surface of the river is quickly filled with a continuous layer of floating ice. In places where there is a fixed ice cover, individual ice floes crawl on it. Others overturn, break and are carried away deep into. There are those that freeze, stopping at the edge, and it begins to move up the river. The water level is constantly rising. The river begins to flood the coastal area. This is how the level reaches its maximum.
You can see what a congestion is at the end of autumn or in the first half of winter. A similar picture is often observed along the banks of such large fast-flowing rivers as the Angara, Amudarya, Narva, Syrdarya and others. According to the frequency of floods due to blockages and the magnitude of the rise of water on the firstthere are two largest lake rivers - the Angara and the Neva.
The duration of the flood can be both a few days and the whole winter. Most often, this period lasts from 1 to 1.5 months. You can see with your own eyes what a zazhor is, if you come to such places at a certain time. Residents of such areas, sometimes, get a lot of trouble. Spilled water freezes and is scooped out as ice and taken out of residential buildings and barns.
Features of the phenomenon
It is precisely due to the sludge that the congestion occurs. What is suga? These are loose pieces of in-water ice and wet snow formed on the river in its upper reaches. A feature of the ice is the formation of ice inside the water during freezing. When the speed of the river flow is high and the temperature is low, the water cools throughout the depth. Intra-water ice floats at temperatures below 0°C and forms sludge (loose accumulations).
Theoretically, many scientists have tried to substantiate the formation of deep ice. For example, Gay-Lussac believed that the formation of such ice occurs due to the drift into the depth of the flow of ice crystals that arise on the surface of the water and are the centers of crystallization. Scientist V. M. Lokhtin continued research on the Neva and substantiated the possibility of formation of deep ice according to the Gay-Lussac theory under conditions of supercooling of the water mass throughout the entire flow.
Knowing what a flood is, people are trying to take appropriate measures to save residential buildings from flooding. Butthey are not always effective or remain only intentions without implementation.
What contributes to the formation of congestion?
When the downstream freezes, the sludge applied from above lingers and begins to build up under the ice cover. This is especially observed near the edge and behind the polynya. The river, as it were, opens its mouth and captures the entire ice and snow mass. This phenomenon is called "burning". Its formation is promoted by shallows, islands, boulders, narrowings, sharp turns. The blockage contributes to the formation of a dam. Water floods all adjacent areas. After freezing, they form frost.
What is the danger of glut? What to do, what measures to take?
With this phenomenon, in addition to the danger of flooding, troubles are piles of ice (sometimes up to 15 meters in height) formed on the banks. They often destroy structures in their immediate vicinity.
Flash events can last a long time, so the consequences of them are serious. Water that has spilled over the coastal area freezes in meadows, in yards and throughout the district, making it difficult to eliminate the consequences of a fire.
How to get out of a dangerous situation and prevent the formation of blockages? It is necessary to carry out on separate sections of the riverbed:
- straightening;
- clearing;
- deepening;
- destruction of ice by explosions (10-15 days before it breaks).
The greatest effect will be the laying of charges under the ice to a depth of up to 5 times greater than the thickness of the ice. A good result brings an embankment on the ice coverground slag with the addition of s alt (15-25 days before the opening of the river).
