stormsurge

Storm surge is an abnormal rise in coastal waters caused primarily by a storm’s winds and reduced atmospheric pressure. As a cyclone or extratropical storm tracks over an ocean, strong onshore winds push water toward the coast and the lowering of sea level pressure causes a dome of water to accumulate near the shoreline. The result can be water levels well above normal tides, and the effect may be further enhanced by wave runup and interactions with tides. The combination of surge, tides, and waves is commonly referred to as a storm tide.

Factors influencing storm surge include storm intensity, wind speed and direction, storm size and forward speed, central pressure, coastal geometry, shelf bathymetry, and the presence of coastal defenses. The severity of surge depends on the overlap of high water with the wind field and can vary along different parts of a coastline. Coastal topography such as sloping shores, estuaries, and shallow shelves can magnify surge heights.

Measurement and forecasting rely on tide gauges, buoys, and satellite data, combined with numerical models that simulate water levels under projected storm conditions. Forecast centers issue surge warnings that guide evacuations and emergency planning. Notable surge-driven impacts have occurred with hurricanes such as Katrina (2005) along the Gulf Coast and Sandy (2012) on the U.S. East Coast.

Mitigation strategies include coastal defenses (levées, seawalls, barriers), enhanced land-use planning, restoration of natural barriers (wetlands, dunes), and effective evacuation protocols. Climate change and rising mean sea level can raise baseline water levels, potentially increasing the impact of future storm surges.