Warnings on the sea water level
On the basis of the sea water level observations made, the warning limits have been set so that the frequency of warnings at the lowest risk level is once a year, at the second risk level once in five years, and at the highest risk level once in 20 years.
Only one warning level is used for low water, but all three warning levels are used for high water.
When the warning is in force, the colour of the coastline on the warning map is changed. Warnings on high and low sea water levels have been issued since spring 2011.
Early warnings concerning the sea water level are compiled for periods extending up to three days.
The warning limits applied to 24-hour warnings and early warnings are listed in the table below:
| | low water | high water | very high water | dangerously high water |
| | once a year | once a year | once in five years | once in 20 years |
| | yellow | yellow | orange | red |
| Northern Bay of Bothnia | -80 | 115 | 140 | 170 |
| Southern Bay of Bothnia | -65 | 85 | 110 | 130 |
| The Quark and Sea of Bothnia | -50 | 75 | 100 | 120 |
| Sea of Åland and Archipelago (Föglö) | -50 | 65 | 85 | 100 |
| Sea of Archipelago (Turku), Western Gulf of Finland (Hanko) | -50 | 70 | 95 | 110 |
| Western Gulf of Finland (Helsinki) | -60 | 80 | 115 | 130 |
| Eastern Gulf of Finland | -70 | 110 | 145 | 175 |
Check the warnings in force on the warnings page. Read more about early warnings, which are also issued on the sea water level.
Flooding of the Market Square in Helsinki on 9 January 2005. Photo: Asko Hutila.
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