Ice conditions

Normal situation Previous ice map Ice map of the previous year Icebreakers

Normal situation


The ice field in the Bay of Bothnia is difficult to force.

In the northern Bay of Bothnia, there is 30-55 cm thick fast ice in the archipelago. Off the fast ice edge there is 10-30 cm thick very close ice to 4 nautical miles southwest of Kemi 1 and Oulun portti and onwards to south. The ice field is ridged and rafted and at the outer ice edge there is a brash ice barrier, difficult to force. Farther out open water.

In the southern Bay of Bothnia there is 10-30 cm thick fast ice in the archipelago. Farther out drifting ice floes in places.

In the Quark there is 10-35 cm thick fast ice and thin level ice in the archipelago. Farther out drifting ice floes in places.

In the Sea of Bothnia there is 5-20 cm thick fast ice in the archipelago.

In the eastern Gulf of Finland there is 10-30 cm thick fast ice in the inner archipelago. In the Gulf of Vyborg and the Gulf of St Petersburg there is 25-40 cm thick fast ice. Farther out 5-20 cm thick very close ice approximately to the line Halli - 5 nautical miles northeast from Seskar.

Icebreakers: Kontio, Otso and Frej assist in the Bay of Bothnia.

Restrictions to navigation: Minimum ice class and deadweight required of assisted vessels:
Tornio, Kemi and Oulu, IA of more than 2000 tons.
Raahe, Rahja, Kokkola, Pietarsaari and Vaasa, IA and IB of more than 2000 tons.
Kaskinen, Loviisa, Kotka and Hamina, I and II of more than 2000 tons.

Vessels bound for Gulf of Bothnia ports in which traffic restrictions apply shall, when passing Svenska Björn, report their nationality, name, port of destination, ETA and speed to ICE INFO on VHF channel 84. This report can also be given directly by phone +46 31 699 100.

Vessels bound for Finnish or Swedish ports with traffic restrictions in the Quark or the Bay of Bothnia shall, 20 nautical miles before Nordvalen Lighthouse, report in accordance with the instructions for winter navigation to Bothnia VTS on VHF channel 67.

The reference map can be changed by clicking on the links above the images. The different maps show the average (= normal) ice conditions (1965-1986) for the period in question, the ice chart of the preceeding week, the corresponding ice chart for the previous year, and the current location of Finnish icebreakers.

The Baltic Sea Now pages display a simplified map of the sea areas by Finland. This map is updated weekly, by Tuesday morning at the latest. The map shows the areas covered by ice and the thickness of smooth ice in these areas. In addition, the map includes isometric displays of temperature gradients by area.

When the Baltic is not covered by ice, the maps show the surface water temperatures in the sea areas and the corresponding temperatures from the previous year. During ice-free periods, the maps are updated irregularly.

More information

Explanation of map's finnish words

  • jäätä: ice
  • vettä: water
  • normaalitilanne: normal situation
  • ahtauma: ice ridge
  • haurasta: rotten ice