Mild January weather keeps lake and river ice dangerously thin

An exceptional start to the year, but colder weather is on the way

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The first weeks of January have been several degrees warmer than average in Finland. There is hardly any ice on lakes and rivers even as far north as Oulu, and the snow-line is running from Pori to Loviisa. However, frost has been predicted for the whole country over the upcoming weekend, and new snow is expected to fall in Southern Finland next week.
      Even the lakes in Northern Lapland have occasional ice-free areas, and according to Finland’s Environmental Administration, only Lake Inari is experiencing normal ice conditions.
      "This is the first time when there is no official ice thickness value at Lauritsala on Lake Saimaa as the ice thickness measurement site was open water", said hydrologist Johanna Korhonen. Normally the ice thickness of Saimaa is 28 cm in January.
      As a result of open waters, no ice thickness observations could be made for instance at Tehinselkä on Lake Päijänne, on Näsijärvi, on Pyhäjärvi at Säkylä, and on Espoo’s Pitkäjärvi, either.
      "Because of changing ice conditions, it is currently not advisable to go out on the ice", Korhonen warns.
     
Even in Lapland, ice thicknesses are generally 5-10 cm weaker than normally. For example near the mouth of the Kemijoki River the recorded ice thickness is only 30 cm, compared with a normal value at this time of 45 cm.
     
According to the statistics of the Finnish Meteorological Institute, the mean temperature in early January was up to 8 degrees higher than is customary in January.
      Precipitation during early January was also exceptionally heavy. In many areas of Southern and Central Finland the precipitation has already been above the entire monthly average. At the same time, the snow-line has moved to the north, currently running from Pori to Loviisa. However, new snow is not expected until next week, when another low pressure area with precipitation is predicted to reach Finland.
     
A new low from the west was expected to bring along a new storm yesterday, even though it was predicted to weaken before it reached Finland. However, stormy winds were forecast for southwestern sea areas for Thursday morning. The heavy winds are expected to reach the Gulf of Finland by Thursday afternoon.
      According to meteorologist Marjo Hippi of the Finnish Meteorological Institute, the winds are expected to reach even land areas but it is not anticipated they will cause destruction.
      Water levels in the rivers and lakes of the province of Uusimaa came down for a while on Wednesday. However, for example the surface of the River Vantaa was still about 180 cm above the normal level.
      According to Leena Villa of the Uusimaa Regional Environment Centre, the water levels are expected to rise again at the end of the current week. However, they are not likely to reach the record levels of last summer.


Links:
  Finnish Meteorological Institute (FMI)
  Monthly hydrological report in January 2004
  Finnish Environment Administration
  Uusimaa Regional Environment Centre

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