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 (yellow), but all three warning levels are used for high water (yellow, orange and red).

Warnings for sea level are drawn up for periods of up to 5 days.

The warning limits 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 (Vaasa) -50 85 110 130
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, Porvoo) -60 80 115 130
Eastern Gulf of Finland -70 110 145 170


Photo: Eija Vallinheimo