Snow in southern Finland is unusually heavy for the time of year – but talk of permanent snow cover is still anyone’s guess

/ Nature
A snowy landscape, a birch tree and a red old outbuilding on the left side of the picture. On the right, a wooden fence and snowy bushes. The sun shines yellow from behind the snow.
Finland is covered in snow. Snowy landscape from Hausjärvi, Puujaan village on 9 December.

Such abundant snowfall in early December is rare in southern Finland. The thickest snow cover, 34 centimetres, was measured today in Virolahti.

Finland is under a blanket of snow.

The region with the most snow at the moment is Kymenlaakso. In Virolahti, the snow depth was as much as 34 centimetres in this morning’s measurement. There is also much more snow than usual in areas such as Uusimaa, where the snow cover is now generally between 17 and 27 centimetres thick.

Such a heavy snow cover has not been common in southern Finland at this time of year for the last ten years. However, comparable snowfall amounts can be found within a thirty-year radius.

Snow situation in Finland 9 December 2022 map.

In the central part of the country, there is a little more snow compared to the time of year than the long-term averages. In northern Finland, on the other hand, there is slightly less snow than on average at this time.

Is there already a permanent snow cover on the ground?

Even though there has been snow in southern Finland for some time, we cannot yet speak of a permanent snow cover with certainty.

According to the definition of the Finnish Meteorological Institute, a permanent snow cover is the longest period of winter, where there is at least one centimeter of snow continuously every day at the observation station in the morning measurement.

The period of permanent snow cover can therefore only fall into later winter, if the early winter snow melts and a new, longer-lasting snow cover comes later.

– In some cases, it is only on the other side of spring that we can tell what the period of permanent snow cover has been, says Ville Siiskonen.

Buses and cars at a snowy street intersection.
Heavy snow slowed down traffic in Roihuvuori, Helsinki, on 9 December.

Permanent snow typically arrives in Kaisaniemi in Helsinki in early January

For example, the beginning of the permanent snow cover at the Kaisaniemi measuring station in Helsinki, i.e. the longest snow period of the winter, during the measurement period of 1991–2020, has on average fallen on January 9.

This year, the first snow fell in Kaisaniemi on November 20. The snow cover has remained in Kaisaniemi since then, but of course it is not yet possible to know how long the snow will remain on the ground.

A person is pulling a child on a stick in a snowy landscape.
In Helsinki, on 8 December, you could take a ride on a sled.

The longest continuous snow cover of the winter stays on the southern coast and southwestern part of the country for an average of 40–90 days. According to Ville Siiskonen, the duration of the permanent snow cover in the interior is 90–130 days on average.

The snow cover isn’t going away any time soon. The weather forecast promises intensifying frost in Finland and more snowfall in some places.