Eastern Siberia, the coldest winters of the northern hemisphere

Siberia (Сибирь), which means "north" in Russian, is geographical shorthand for “very cold.” But even by Siberian standards, what’s happening regarding extreme temperatures in the eastern Siberia hamlet of Oymyakon right now is difficult to believe—and it begs the question of just what makes this part of the world so freaking cold.

emperatures have been topping out at minus-40 degrees Celsius in Oymyakon, home to 500 permanent residents. The village officially bottomed out at minus-59 degrees Celsius earlier this week, though local residents reported temperatures as low as minus-67 degrees Celsius. That’s just shy of the minus-68 degree reading recorded in Oymyakon in 1933, the coldest temperature ever recorded outside of Antarctica.

The cold has left at least two dead, which seems like a low number, given that frostbite can set in in just minutes.

The town is known for its extremes but the daily average temperature from November to March is well below zero degrees Fahrenheit. It holds a bevy of other cold weather distinctions, too. One might wonder what makes the weather in Oymyakon so special, as well as why anyone would want to live there. The answer is a mix of geography and weather, at least as far as the weather is concerned. Why people live there is a whole other story.

Let’s get the obvious out of the way first. Oymyakon is pretty far north, and places in the north get cold in the winter owing to a lack of sunlight. But that alone doesn’t explain it. It’s not even the furthest north point in Siberia, and it sits below the fabled Arctic Circle.

We need some special sauce from the atmosphere. Eastern Siberia is also home to what weather forecasters call the Siberian High, a semi-permanent ridge of high pressure that camps over the region for much of the winter.

We’ve seen high pressure lock in warm dry weather in California this winter. The Siberian High keeps things pretty dry, but warm, not so much. Further west, storms are more frequent. That mixes the atmosphere, and allows warmer air that comes with them from the North Atlantic to regularly flush the worst of the cold away.

But the high steers those storms away from eastern Siberia for most of the winter. That means there’s no warm air for the region to draw from. Instead, the high pressure ensures cold, dry air stays on tap, creating a self-reinforcing cycle of deepening chill.

The snowpack that usually forms in the fall only makes things worse, reflecting the very limited warmth from the few hours of sunlight a day back into space. That’s the weather setup stacked against any warm air that may attempt to take hold in the region.

But what makes Oymyakon a unique island of cold in a veritable frozen sea is its geography. Landlocked areas tend to be colder than coastal locations in winter in most parts of the world. And Oymyakon is landlocked in eastern Siberia, the heart of the coldest part of the world. Cut off from storms to the west, it’s also too far from the relatively warm seas to the north and east to get a heat boost.

Oymyakon’s final secret weapon for attracting cold is its location in a valley. This valley—or almost any valley, really—is a magnet for inversions, a process where cold air sinks to the valley floor while warm air rises and acts as a cap. In other valleys like Salt Lake City, that can lead to major pollution issues, in addition to colder-than-normal conditions until a storm comes to mix things up. In Oymyakon, it’s a recipe for record-setting deep freezes.

A 1991 study found that the eastern Siberia is home to the most common and strongest inversions in Eurasia, due to this combination of weather and topography. And Oymyakon is the bullseye of the worst of it.

A study published in 2011 looked at the temperature difference in the valley Oymyakon sits in vs. the surrounding mountains. The researchers found that, though the mountains are less than 1,000 feet higher than the valley, the temperature could be up to 36 degrees Fahrenheit warmer in the winter time.

As the Siberian High clears out in spring and weather patterns allows the atmosphere to mix more, the inversions basically disappear. A graph in the 2011 study—which by the way, also shows that climate change is melting glaciers in the world’s coldest inhabited place—makes this shift abundantly clear.
Ref.
https://earther.gizmodo.com/why-the-eastern-corner-of-siberia-is-the-coldest-inhabi-1822160684