Storm surge is the rise in sea level above normal astronomical tide caused by hurricane winds pushing water toward the coast and the suction effect of the low central pressure. Combined, these can raise the sea 3–8 metres.
The deadliest hazard
Storm surge causes over 50% of deaths in tropical cyclones, exceeding wind and rain. Devastation depends on cyclone intensity, coastal topography (low coasts are most vulnerable), bathymetry, and coincidence with high tide. Hurricane Katrina (2005) produced an 8.5 m surge along the Mississippi coast.