Whether it is cold in winter in Russia, nothing new under the sun. But since the beginning of the year, the values recorded, polar, explode the averages and extend on the territory. In the Moscow region, it was down to -29 ° C while Siberia fell below -60 ° C on Tuesday.
Siberia, a gigantic territory more than 3,000 km east of Moscow, is used to freezing cold. It is even home to the coldest city in the world, Oymyakon, in Yakutia, in the northeast of the region. Average temperatures in this region are -45°C in January. Enough to make it the coldest territory in the northern hemisphere, followed by certain areas of northwestern Canada. In winter, it is also the second coldest region on the planet after Antarctica. “However, the climate is very contrasted between winter and summer, with annual temperature variations that can reach 80°C. Indeed, brief hot spells can raise the temperature to 35°C in summer, in these sectors where it is -60°C in winter.reports the Weather Channel.
Negative anomalies of -30°C
If the polar cold seizes the Eastern Siberia every winter, bringing the temperature down to -55°, the cold has, since the beginning of January, spread to all of Eurasia, as far as Moscow, in the west of Russian territory. And negative anomalies of -30°C have been recorded in the heart of Siberia, much more than the hot anomalies, noted elsewhere in the world, such as in Europe, North America and China.
“In total, on the scale of Siberia, the current temperatures make it the most intense cold snap since 1982 in Yakutia”, explains the Weather Channel. Moreover, “the minimum and maximum temperatures [-57° la nuit et -50 °C le jour] more generally make it the strongest cold wave since 1994. The -62 ° C recorded on Tuesday is a monthly record for the Zhilinda station, since the opening of the current weather station in 1942.
Despite the exceptional nature of these temperatures, the absolute cold records in Siberia are not threatened. “In Russia, the cold record that we find in the archives dates back to January 26, 1926, with -67.8 ° C in Oymyakon and Verkhoyansk”, recalls the Weather Channel. Just like the brief – but intense – cold snap that gripped Americans at Christmas, which had fallen to -20°C below the average, the current situation in Siberia is -30°C below the average. “So much so that there is no longer a corresponding color on the weather maps”details the Weather Channel. “On the other hand, hot anomalies are very widespread and long-lasting. [souvent de +10° à +14 °C en Amérique du Nord actuellement, ainsi qu’en Chine]». The enormous contrasts thus strongly affect the northern hemisphere. The southern hemisphere is more temperate.
Counter-intuitive, these freezing temperatures at a time when the planet is overheating are the result of a well-known phenomenon, the “polar vortex”. Global warming is a fundamental trend, which pushes temperatures upwards over the decades. This does not prevent cold epiphenomena from occurring, which are much less numerous than hot anomalies on the planet. This trend should continue in the future, according to the IPCC scenarios.
Siberian High
“Mechanically, the ripples of the jet stream, [un «tube de vent» très fort d’ouest, ndlr], are responsible for these communicating vase effects, carrying mild air to the north and cold air to the south. But this is not enough”explains the Weather Channel. Fluctuations in the tropopause, the layer that delimits the troposphere in which we live and the stratosphere above, may also partly explain these intense cold spells. Variations of this boundary layer are capable of plunging the icy air of the stratosphere towards the ground. Or the famous “polar vortex”. Once this mechanism is triggered, a powerful anticyclone sets in and traps the cold at ground level, known as the Siberian anticyclone.
According to the weather forecast, this cold wave should gradually ease and shift towards China, in Southeast Asia, which is currently experiencing abnormally mild temperatures. Russia will return to season averages.
Extreme cold wave grips Siberia and rages as far as western Russia