Finland’s worst wildfire in more than half a century scorched the country’s northwest for a fifth day on Friday, tearing through forests left dry by record summer heat.

An extended period of hot, dry weather is affecting the harvest outlook and impacting grain growth. Even the wild berry season, which was off to a good start, may be in peril.

Strong winds have created a picturesque wall of ice on the shore of Lake Pyhäjärv. "This often happens at this time of year on the shores of larger lakes and on the sea shore," Huutonen said, adding that there were gale force winds in the area over the weekend.

A high of 14.7 degrees Celsius was measured in the southwestern city of Pori on Monday night.

An exceptionally warm air current from the southeast has kept days and nights unseasonably mild in southern and central Finland since last week. Meanwhile the north of the country has been shivering with rain and temperatures in the single digits. The highest reading in decades was recorded in Kokemäki, southwest Finland.

More than 40,000 households faced blackouts overnight.

Reports of symptoms such as diarrhoea and vomiting are being investigated in South Ostrobothnia.

A total of 140 crashes and other accidents involving elk have been reported in the last week alone, police said, especially in the area around Pyhäjärvi lake near the town of Säkylä in the southwest of Finland.

A fire chief in the south-west said firefighters were called to several fires a day in recent days, saying that all were caused by people who ignored warnings.

BirdLife Finland reports that Finnish populations of the common pochardhave plummeted by 80 percent in 20 years.

Packed ice crystals have pushed up water levels on the Kokemäki River, soaking some buildings in Huittinen and Pori.

Spring - or rather thermal spring - could be arriving to Finland as early as this week in southern and western areas.