Officials say that heavy slush on the Kokemäki River has caused the worst winter flooding in south-western Finland in over a decade.
On Saturday the situation had improved in town of Huittinen, inland from Pori in the Satakunta region. The level of the Kokemäki River there had declined by about half a metre from that of the past few days.
The improvement came after military engineers exploded dams of tightly-packed slush and ice on the river and slowed its flow. Slush flooding occurs when ice crystals become tightly packed into dams of slush, which block the base of the river, pushing water levels up.
In the city of Pori on the west coast, water levels remained at Friday's flood level, but officials expect some relief soon. On Wednesday evening, flood waters threatened homes in Pori's Kivini district.
Water has entered some structures in Huittinen and Pori, mostly holiday cabins. However no damage is reported to residential buildings.
Worst since 2005
The situation is the worst since at least 2005, says Juha-Pekka Triipponen, senior water resource expert at the Southwest Finland Centre for Economic Development, Transport and the Environment (ELY Centre).
"Historically the worst slush flooding situations have been around this point of the winter, in 1974-75 and in 2004-05," he told the Finnish News Agency STT on Friday.
Triipponen says the situation is now at least as bad as that in the winter of 2004-05.
Ice cover should help
Colder weather is expected to improve the situation by forming a solid ice cover on the river. Readings of around -10 degrees Celsius are forecast for the rest of the weekend and early next week.
Around the middle of next week, though, temperatures are to set to rise again, potentially causing more local flooding.