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)
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| low (yellow) |
high (yellow) |
very high (orange) |
dangerously high (red) | |
| Kemi, Oulu | -80 cm | 115 cm | 140 cm | 170 cm |
| Raahe, Pietarsaari | -65 cm | 85 cm | 110 cm | 130 cm |
| Vaasa | -50 cm | 85 cm | 110 cm | 130 cm |
| Kaskinen, Pori, Rauma | -50 cm | 75 cm | 100 cm | 120 cm |
| Föglö | -50 cm | 65 cm | 85 cm | 100 cm |
| Turku, Hanko | -50 cm | 70 cm | 95 cm | 110 cm |
| Helsinki, Porvoo | -60 cm | 80 cm | 115 cm | 130 cm |
| Hamina | -70 cm | 110 cm | 145 cm | 170 cm |
N2000 (BSCD2000)
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| low (yellow) |
high (yellow) |
very high (orange) |
dangerously high (red) | |
| Kemi, Oulu | -72 cm | 123 cm | 148 cm | 178 cm |
| Raahe | -57 cm | 93 cm | 118 cm | 138 cm |
| Pietarsaari | -59 cm | 91 cm | 116 cm | 136 cm |
| Vaasa | -44 cm | 92 cm | 117 cm | 137 cm |
| Kaskinen | -41 cm | 84 cm | 109 cm | 129 cm |
| Pori, Rauma | -39 cm | 86 cm | 111 cm | 131 cm |
| Turku | -36 cm | 85 cm | 110 cm | 125 cm |
| Föglö | -39 cm | 76 cm | 96 cm | 111 cm |
| Hanko | -32 cm | 88 cm | 113 cm | 128 cm |
| Helsinki, Porvoo | -39 cm | 101 cm | 136 cm | 151 cm |
| Hamina | -49 cm | 131 cm | 166 cm | 191 cm |
The warning limits in N2000 height system change some millimeters every year.