Southern Finland could see heavy snowfall over the coming days as a low-pressure system moves in from the southwest, according to Yle meteorologist Anniina Valtonen.
She said the weather system will pass over the south-west coast, with its centre remaining over the Baltic Sea.
"Because the sea is unfrozen, the air is cold and the wind is blowing from the east, a snow-cannon effect will form over the Gulf of Finland," Valtonen said.
The phenomenon is expected to create bands of intense snow showers drifting towards the coast. Large snowfall accumulations are forecast between Southwest Finland and Uusimaa, and driving conditions could become extremely hazardous.
"At worst, more than 40 centimetres of snow could fall by Saturday," Valtonen warned.
Fintraffic's road traffic centre has issued a warning that driving conditions will deteriorate from late Friday night. Valtonen said the light, powdery snow will both reduce visibility and make road surfaces slippery.
"This type of snow does not stick to anything, as the crystals are very fine and polish and ice the road surface," she said.
"If this forecast materialises, conditions will be extremely dangerous."
Temperatures in southern Finland are expected to ease slightly as the snowstorm arrives, before falling again after Sunday. Valtonen added that even small changes in wind direction could significantly affect where the heaviest snowfall occurs.
"If the wind direction changes even slightly, the snow bands will remain over the Gulf of Finland, and coastal areas will see more typical snowfall," she said.
