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 (yellow) is once a year, at the second risk level (orange) once in five years, and at the highest risk level (red) 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). The warning levels are set for the 14 observation stations.

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

Sea level warning limits

The warning limits are listed in the tables below referenced to the theoretical mean water (MW) and N2000 (BSCD2000) systems.

Theoretical mean water (MW)

station	low (yellow)	high (yellow)	very high (orange)	dangerously high (red)
Kemi	-80 cm	115 cm	140 cm	170 cm
Oulu	-80 cm	115 cm	140 cm	170 cm
Raahe	-65 cm	85 cm	110 cm	130 cm
Pietarsaari	-65 cm	85 cm	110 cm	130 cm
Vaasa	-50 cm	85 cm	110 cm	130 cm
Kaskinen	-50 cm	75 cm	100 cm	120 cm
Pori	-50 cm	75 cm	100 cm	120 cm
Rauma	-50 cm	75 cm	100 cm	120 cm
Turku	-50 cm	70 cm	95 cm	110 cm
Föglö	-50 cm	65 cm	85 cm	100 cm
Hanko	-50 cm	70 cm	95 cm	110 cm
Helsinki	-60 cm	80 cm	115 cm	130 cm
Porvoo	-60 cm	80 cm	115 cm	130 cm
Hamina	-70 cm	110 cm	145 cm	170 cm

N2000 (BSCD2000)

station	low (yellow)	high (yellow)	very high (orange)	dangerously high (red)
Kemi	-73 cm	122 cm	147 cm	177 cm
Oulu	-73 cm	122 cm	147 cm	177 cm
Raahe	-58 cm	92 cm	117 cm	137 cm
Pietarsaari	-60 cm	90 cm	115 cm	135 cm
Vaasa	-45 cm	90 cm	115 cm	135 cm
Kaskinen	-42 cm	83 cm	108 cm	128 cm
Pori	-40 cm	85 cm	110 cm	130 cm
Rauma	-40 cm	86 cm	111 cm	131 cm
Turku	-36 cm	84 cm	109 cm	124 cm
Föglö	-39 cm	76 cm	96 cm	111 cm
Hanko	-32 cm	88 cm	113 cm	128 cm
Helsinki	-39 cm	101 cm	136 cm	151 cm
Porvoo	-39 cm	101 cm	136 cm	151 cm
Hamina	-48 cm	132 cm	167 cm	192 cm

The limits in N2000 (=BSCD2000) height system change yearly some millimeters.