The Finnish Environment Institute reports that following rains this past week, the volume of water in Kokemäenjoki river, which flows through the west coast city of Pori, is around three times its normal level. Last weekend, it was only about 20cm below the flood mark.
Heavy rains have also pushed the volume of water in rivers in the southwest of the country to record highs for the year. Along the south coast, the Kymijoki river is carrying nearly twice its usual volume of water. The Environment Institute's chief hydrologist Bertel Vehviläinen believes that most of the country will see flooding if present weather forecasts are accurate.
"If it is mild and rainy, and the snow melts, there could be flooding along the coasts, in South Häme and in Ostrobothnia. Flooding has already been seen mainly in southern and southwestern Finland, but so far not in Ostrobothnia," explains Vehviläinen.
Sea levels have also risen. For example, at Hamina the sea level is some 80cm above normal.
With major lakes also filled to the brink, rivers will likely be overflowing their banks.
Cold periods this winter will further exasperate the situation, as low temperatures lead to the formation of slush in swiftly flowing rivers.
"The whole winter's going to be difficult," says Juha Pohjoisaho of the Southwest Finland Centre for Economic Development, Transport and the Environment. "Ice cover on strongly flowing rivers will be weak, or not form at all, instead creating slush. This may raise water levels significantly in the lower reaches of rivers, in some places by as much as one and a half metres."
Finland has not seen such a rainy early winter since 2012, and before that in 2008. Pohjoisaho believes that wet winters will become more the rule than the exception along the south coast.
"The nature of winter has change to the extent that winter floods are here to stay. As recently as in the 1980s, there were more periods of sub-zero temperatures and they lasted longer."