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.