Monitoring swimmer safety

How to Use

The website Swimmer Safety Egmond is currently unavailable. For usage, the only requirements were an internet connection and installation of the Google Earth plug-in (will automatically be indicated when needed). The website is known to encounter problems when accessed with Internet Explorer. For best visualisation, the use of Google Chrome is advised.


The muienradar (‘rip current radar’) website provides general background on rip currents, gives an introduction to the CoSMoS model system and presents the 2-day hydrodynamic forecast for Egmond beach in a Google Earth viewer. Under the real-time forecast, the user can select for which model the results will be visualized. Subsequently, he can inspect the forecast data in map view and animate the results in time. For selected observation stations, timeseries of the model predictions can be inspected and the model performance can be assessed compared to field observations. Please note that it may take a while to load some of the larger model data sets.

At the most detailed model level, the offshore directed current velocities are translated into rip current warnings. If a certain threshold is exceeded, a warning marker will appear on the map at the rip current location. In the present setup, velocities between 0.15 and 0.3 m/s are considered a moderate rip strength, velocities between 0.3 and 0.5 m/s a strong rip strength and velocities above 0.5 m/s a very strong rip strength. A time-stack with offshore directed current magnitudes along the coast shows where and when rip currents are to be expected and allow for a quick inspection by the lifeguards.

It should be noted that the warnings do not define swimmer safety in general, but only give a measure of the absolute current magnitudes. Clearly, the risk to an individual person strongly depends on his/her level of fitness and environmental conditions, such as water temperature and wind direction. Therefore, the presented warnings are not meant to replace the judgment of the lifeguards or of the beach visitor but can be used as an additional source of information.


A demo of the muienradar can be seen here: