1 May 2021 wildfire south of Oymyakon (Yakutia)
© Pierre Markuse
1 May 2021 wildfire south of Oymyakon (Yakutia), the coldest inhabited settlement on Earth.
Could burning ground in an area as extremely cold as Oymyakon be caused by zombie fires?

The air temperature in the Oymyakon district of Yakutia is still negative at nights, with daytime just about climbing over 1C.

Snow is beginning to melt, but rivers are still locked in ice for at least a couple weeks more - which is completely normal for Oymyakon, the coldest permanently inhabited settlement on Earth.

What is abnormal is the sight of a dozen wildfires burning a short distance north and south from this famous Pole of Cold.

The first was registered as unusually early as 29 April by the settlement of Teryut, a short distance north from Oymyakon.

Sentinel-2 satellite caught sight of frozen Indigirka River, snow-covered mountains, and ominous dark-orange dots scattered along the valleys.

The second set of fires was recorded south of Oymyakon and even closer by distance (within 20km, or 12 milds) on 1 May.

Last summer was one of the worst in the history of Yakutia for the number of wildfires, with many registered above the Arctic circle.

Russia's largest and coldest region reported fires all around its territory, with a massive blanket of smoke visible from space in the far north beside the Arctic Ocean.

At the end of autumn 2020 a report in Tomponsky Vestnik newspaper made clear that one such fire was still burning outside the village of Udarnik - the area that suffered badly in summer wildfires.

Video and pictures show August 2020 wildfires in Svatay, extreme north of Yakutia, and other northern villages in Yakutia:

The video, filmed in November at -25C (-13F) showed pillars of smoke rising above a field outside the village, with worried residents commenting that summer fires had not stopped.

Several months later we asked local journalists to check if the smoke was still visible in the same location - and it was, with the ground feeling 'like rubber' as they walked along a field.

The video below was filmed at -30C (-22F) after months of extremely cold winter with air temperatures plummeting in December and January 2021 to as low as -60C (-76F).

This kind of fire - most often in peat, or young coal, or a mixture of both - is often described as a 'zombie fire'.

Collapsing ground and thawing snow above a zombie fire outside the village of Udarnik, filmed in February 2021, months after it was first noticed in November 2020:

Such blazes can go on for weeks and months. In some situations they are next to impossible to extinguish.

Siberia has a number of such fires - further south, but now they are present in the far north.

'This winter peat and charcoal underground fire outside Udarnik was caused by summer wildfires that didn't stop till late Autumn. It wasn't diminished by weeks of rain, which is typical for peat fires as they can go many metres down, creating extremely dangerous burning 'pockets' where a man or an animal would burn alive within minutes. Peat fires don't need oxygen from outside, and 'like' cold snowy winters because snow acts like a blanket that supports burning', said ex-forester Lyubov Vasilyeva, from the Tomponsky district of Yakutia.

Lyubov, 62, believes that it was the collapse of the Soviet Union that started a long chain of events leading to the current zombie fires.

'There was a system of controlled burning of dry grass, with specialists - who had maps with peat bogs and coal deposits marked - supervising the process,' she said, recalling the past.

'It died in the early '90s, and nothing new was created, with people burning grass uncontrollably and without knowledge.

'This results in massive summer wildfires, with some of them turning into zombie fires', she said.