Image: Antti Eintola / Yle

Finland's lakes have been freezing behind schedule this winter, according to Finland's Environmental Administration, which urges those venturing out on the ice to exercise caution.

In Lapland, most lakes iced over two to three weeks behind schedule in November, while waters in central and southern Finland froze by mid-December, some two weeks later than usual.

Story continues after photos.

Image: Antti Eintola / Yle

Image: Antti Eintola / Yle

Image: Antti Eintola / Yle

Image: Antti Eintola / Yle

Image: Antti Eintola / Yle

Thin ice

Lapland's lakeshores have an ice thickness of 20 to 40 centimetres, the thinnest recorded since 2011.

The ice cover in central areas and the Kainuu region is around 25 centimetres, while measurements put the ice depth on southern Finland’s lakes at less than 20 centimetres.

Image: Antti Eintola / Yle