Expert called his version of the causes of the landslide in Almaty
About when should we fear the floods, why they are impossible to predict and the cause of this natural disaster in an interview Today.kz said lead researcher RSE “Kazhydromet”, PhD Institute of ecology and climate, Professor Boris Stepanov.
Professor Stepanov was studying the SEL for the past 45 years. And, in his opinion, the heat wave could hardly be the cause of recent landslide in Almaty.
“To believe that the cause of the landslide was a heat wave, I can’t. Mudflows, associated with temperatures, right only twice in the last 40 years. During those 42 years there have been many occasions when the heat was the same as now, or worse, but anything related to heat occurred. Occurred breakthroughs, even when it was over the summer, and the autumn came”, – said Boris Stepanov.
In his words, to predict the similarity of debris flow is impossible. The study of glaciers and moraines requires a large amount of funds, so it is much cheaper and more efficient to empty a potentially dangerous lake.
“To predict a breakthrough no one can, because no one moraine lake does not explore. To explore the glaciers and moraines on the subject of forming a subsea discharge channels is very expensive. The lake is much cheaper and more efficient just to empty than to seek out all these channels and then to predict – will burst or not burst,” says the Professor.
Doctor of Sciences Boris Stepanov called Almaty lake, which is “to fear”.
“To be afraid of people need moraine lakes No. 6 and No. 13 bis. For example, the same lake No. 6 “Kazselezaschita” empty to within five meters, while its depth is about 20 meters. And to empty it more the way it’s done now – i.e. siphons – impossible. At this depth the pressure is much lower, so that a maximum of five feet to lower the lake level, and everything else remains the siphon stops working. This is only a partial emptying, which to some extent helps to reduce the damage from the outburst of lake,” says the Professor.
According to doctors, the conditions for the breakthrough of waters are formed for years and even decades. As soon as a lake is born, it immediately begins to grow, and with it begin to grow and vnutrijeludockova vnutrigornye the channels through which this lake sooner or later empty the natural way.
“To say how dangerous it is or that the lake is impossible. Normal hydrometeorological forecast assumes that, according to him, will know when the happens the flood and about where. And when giving forecasts in General, in Almaty region and do not specify a particular place, in my opinion, this is not a forecast. Can you imagine Almaty region and how many gorges? Well all put on the ears?”, – says Stepanov.
Descended at night on July 23, Almaty SEL Boris Stepanov considers as “medium”. And the reason for his breakthrough, according to the scientist, is that this gathering had been prepared for years.
“SEL is a normal phenomenon in the mountains. The fact is that there are three levels of accumulation of the sediment. The sediment referred to all the stones, huge and small, and clay. The first level is the high altitude areas, where the valley bottom glaciers and avalanches deliver this material. The second level – the cones-the cones on which we live, all cities are located on the cones-the cones. Move to the upper tier on the middle tier are the mudslide, it is a normal natural process. Yesterday SEL can be classified as secondary, because he still essentially got to the cone-removal. This gathering of debris flow have been prepared for years,” said the scientist.
As said Boris Stepanov, sat is a multifactorial process and the presence of precipitation does not always mean absolute probability of debris flow.
“It all depends on where the precipitation fell. If liquid precipitation fell in the Alpine zone, is a high probability that SEL will be. If somewhere in the middle mountain zone, where there are trees, there is soil and vegetation is intercepted by the liquid, and the probability of debris flow is less. And at the bottom, where there is no vegetation, and there sat a small, because small area. If sediments cover all areas, we can expect a catastrophic debris flow,” continues the source.
The last truly catastrophic mudslides, according to the doctors, went to Almaty in 1921.
“Understand, the temperature influences precipitation and phase – solid or liquid, then you need to consider pre-wetting, how long ago were the rains, the rains. Where is the snow line – a very important point. If precipitation is assumed at the beginning of may, we expect that sat will occur in the highlands, because there’s still snow,” he says.
As noted by Boris Stepanov, in recent years, cases of water-ice debris flows, typical for the winter period. Such mudflows can be generated within the city.
“The most dangerous situations occur most frequently from June to August. But there was a breakthrough in September. In General, the greater the probability of liquid precipitation in the mountains, the more likely the mudslide,” said the scientist.
In addition, he reports that mudslides may become more frequent due to the fact that glaciers are retreating, and, as a result, lakes are formed much faster, which increases the likelihood of a breakthrough.