Coastal flooding occurs due to storm surges generated by tropical and extratropical cyclones on the globe. The meteorological forcing fields for the generation of storm surges are the tangential surface wind stress on the ocean surface and the normal atmospheric pressure gradients associated with the weather systems. The large scale forcing from the cyclones is referred to as the synoptic scale and storm surge prediction from synoptic scale forcing is well developed and is reasonably satisfactory around the world. However, coastal flooding also occurs from weather systems, with forcing on a meso-scale and also from remote forcing. It is proposed here that the term ''Storm surge'' be used to only refer to coastal flooding from synoptic scale forcing and the terminology ''Rissaga'' be used for coastal flooding from meso-scale forcing. For flooding due to remote forcing, a new term ''Kallakkadal'' is proposed.

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The mechanisms of berm development along a microtidal‐high energy beach is examined. Such a beach with medium‐sized sand and monsoon wave‐controlled profile at Valiathura, south‐west coast of India, is selected for this study. The waves which very rarely fall below 1 m, often exceed 4 m during the monsoon period of May to October. The erosion‐accretion pattern of the beach shows a cyclicity and the berm development is mainly due to the onshore migration and welding of longshore bars on to the beach following the monsoon rough season. The stages of berm development in the present microtidal beach are more or less similar to the model presented by Hine for a mesotidal case, except for the following intermediate additional stages. The longshore bar develops due to the erosion of beach when the wave steepness was above 0·04, gets flattened when it falls below 0·04, and then reforms nearer to the shoreline as a swash bar. This reformed bar gets divided and the inner bar gets welded on to the beach, followed by the outer bar developing the berm. During the onshore migration of the longshore bar and berm development the beach face becomes partially reflective with the surf scaling parameter, εb between 2·5 and 33. The inshore is dissipative with the inshore surf scaling parameter, εs≫33. The offshore side of the longshore bar is partially reflective with its surf scaling parameter, εbar between 2·5 and 33. The breakers are spilling or plunging. Vertical growth of the berm is mainly due to the changes in swash‐limit caused by the variations in wave steepness, breaker height and type. Vertical growth stops when the beach‐face attains equilibrium with the grain size‐wave energy relationship, and a wave steepness below 0·02 helps to sustain this state.

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