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In addition to point-like observations, the ice situation map shows the estimates calculated by the forecast model. You shouldn't go to the ice based on the map estimates alone, because the local variation can be big! Especially immediately after freezing, the ice can be much weaker in currents and backwaters than, for example, in coastal areas. In spring, when the snow has melted, the sun can make even the thickest ice brittle in just a couple of hours.

Ice situation 12.2.2025

The ice cover has largely increased or remained unchanged

In the first week of February, the ice cover on water bodies at several observation stations had increased since the measurement at the end of January. Despite this increase, the ice cover was still around ten centimetres thinner than the average thickness of the season, especially in many lakes in Southern Finland. In the measurements of 10 February, the total ice cover thickness varied between 37 cm and 63 cm at observation sites in Kainuu, North Ostrobothnia and Lapland, and the ice cover was close to the average seasonal thickness, with the exception of Lakes Unari and Inarijärvi, where the ice thickness was almost 10 cm thicker than average. The ice cover in Lake Kilpisjärvi was also more than 10 cm thinner than average. In Central Finland, the ice cover varied between 35 cm and 53 cm, and the ice cover was close to the average thickness or slightly thinner than average. In Southern Finland, the ice thickness varied between 16 cm and 27 cm, mainly remaining 10 cm thinner than average. The ice thickness is monitored three times a month during the period of ice cover, always on the 10th, 20th and 30th day.

The estimated ice situation is based on observations.

The Finnish Environment Institute updates the estimate of the ice situation on this page three times a month. The estimate is based on ice thickness measurements at 46 observation sites in different parts of Finland. The ice thickness is measured approximately on the 10th, 20th and 30th day of every month.

You can view the latest observations on the ice situation map (available in Finnish and Swedish). Everyone can also record their own ice observations, and they will be visible on the map. The Finnish Environment Institute does not verify these observations. You should not go on the ice solely based on the estimates and observations on the map because ice quality and thickness vary greatly even within the same lake and between different waterbodies.

You can observe the general development of the ice situation by a computational estimate of ice thickness, i.e., the colours on the map. The estimate is made by modelling, and it utilises ice thickness observations as well as weather data and forecasts, for instance. It is not possible to determine the actual ice thickness of any waterbody based on the ice situation map. The ice thickness observations are only representative of the specific site on the date of the measurement and are therefore indicative and cannot be extrapolated to large areas.

Further information

 

Ihmiset ulkoilevat kevätjäällä Siilinkarin majakan edustalla Tampereen Pyhäjärvellä

Stay safe on ice from autumn till spring

If you intend to go out on ice, you should always make sure that it is strong enough on the route you intend to take. Get to know the properties of ice in different seasons and pay attention to possible hazards.

Autumn ice

The water starts freezing in autumn when its surface temperature drops below zero. Shores and bays are the first to freeze over, while any deep areas and places with a current get their ice cover last. It is typical for ice thickness to vary in different areas of a lake or the sea in autumn. Measure the thickness of the ice on your route to be sure that it will carry you. Transparent clear ice must be at least five to ten centimetres thick before it carries a person walking on it.

Spring ice

As the air grows warmer and the sun’s radiation becomes stronger in spring, the snow and ice cover starts to melt. Once the snow is gone and solar radiation starts melting the ice, its structure becomes more fragile and cavities appear in the ice layer, and you can no longer conclude the bearing strength of the ice by measuring its thickness. Even if it were 20 to 30 centimetres thick, the ice can be too fragile to carry the weight of a person.

Hazardous areas

Particularly hazardous areas are straights, deep areas and places with a current, including at river mouths and near springs, sewers and stormwater drains, where the ice may remain thin throughout the winter. You should also monitor the ice thickness near large stones, docks and other structures as well as aquatic plants. Shipping lanes, and cracks and holes cut in the ice, are dangerous even in mid-winter. Snow cover makes it more difficult to spot areas of weak ice.

Fun facts about ice