When there is an intense low pressure system off the coast it reduces the weight of air pushing down on the ocean and sea levels will rise higher than would occur under normal tidal conditions. In the most severe low pressure events the ocean can rise between one and two metres and if this happens during a high tide then the ocean will reach further inland than normally seen. This can cause flooding of low lying coastal communities. An example occurred in June 2007 where flooding at Lakes Entrance was largely influenced by coastal flooding as shown in the photograph below:
Often the flooding is made worse because the intense low pressure system creates strong winds and rain. The winds whip up large waves and push the ocean towards the coast. When the rain falls on the land it flows down rivers and through lakes to the coast but cannot flow into the sea because the sea level is higher than normal and these flows add to the flooding.