When one fine winter frosty day a mist spreads over a river that has not yet been frozen, and ice floes and clods of sludge calmly drift down the river, suddenly the water level begins to rise due to the thickening ice drift - the inhabitants of the coastal areas know that the time has come to catch. What is characteristic of this phenomenon and how to get out of it?
Description of the phenomenon
From the moment the gorge began, very quickly the surface of the river is filled with floating ice in a continuous layer. In places where there is a motionless ice cover, individual ice floes crawl onto it. Others are overturned, broken, and carried deep. 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 territory. So the level reaches its maximum.
You can see what a glaze is in late autumn or in the first half of winter. A similar picture is often observed off the coast of such large rivers with a fast current, such as the Angara, Amu Darya, Narva, Syr Darya and others. In terms of the frequency of floods due to floods and the magnitude of the rise in water, the two largest lake rivers - Angara and Neva - are in the first place.
The duration of flooding floods can be several days or all winter. Most often, this period lasts from 1 to 1.5 months. You can see firsthand what a glaze is, if you come to such places at a certain time. Residents of such areas, it happens, get a lot of trouble. Spilling water freezes, and it is punctured as ice and taken out of residential buildings and sheds.
Features of the phenomenon
It is due to the sludge that there is a glitch. What is sludge? These are loose pieces of water and wet snow formed on the river in its upper sections. A feature of the glaze is the formation of ice inside the water during ice formation. When the speed of the river is high and the temperature is low, the water cools down the entire depth. Intra-water ice at a temperature below 0 ° C floats and forms a sludge (loose clusters).
Many scientists have tried to theoretically substantiate the formation of deep ice. For example, Gay-Lussac believed that the formation of such ice occurs due to the deep drift of ice crystals that arise on the surface of the water and are crystallization centers. Scientist V. M. Lokhtin continued research on the Neva and substantiated the possibility of deep ice formation according to the Gay-Lussak theory under conditions of supercooling of water mass throughout the entire stream.
Knowing what a jam is, people are trying to take appropriate measures to preserve residential buildings from flooding. But they are not always effective or remain only intentions without embodiment.
What contributes to the formation of gorges?
When the bottom of the current freezes, the sludge applied from above is delayed and begins to grow under the cover of ice. This is especially observed at the edge and behind wormwood. The river, as it were, opens its mouth and captures the entire ice and snow mass. This phenomenon is called "zhazh". Its formation is promoted by the shallows, islands, boulders, narrowings, sharp turns. A blockage contributes to the formation of a dam. Water floods all adjacent areas. After freezing, they form ice.
