What is a Storm Surge?
Author: Mark Sheppler A storm surge is a tide level change primarily brought about by a storm, particularly of the tropical cyclone ilk. In a storm surge, the sea level increases above and beyond the normal sea height, creating huge walls of water that can exacerbate the risks of the storm. How a Storm Can Cause a Storm Surge Storm surges can occur in the case of a storm, big or small. They are more likely, however, in a tropical cyclone type of storm. The storm has different results, each of which becomes a factor that influences the characteristics of a storm surge. All the following factors interact with each other to determine how high and how powerful a storm surge is going to be Wind The wind is the principal cause of a storm surge. The wind blows over the water and causes a surge of gigantic waves. The fact that the wind is moving in a spiral rotational direction reduces the sea water height downwind and increases the water height upwind.
Storm surge is water that is pushed toward the shore by the force of the winds swirling around the storm. This advancing surge combines with the normal tides to create the hurricane storm tide, which can increase the mean water level 15 feet or more. Additionally, wind driven waves are superimposed on the storm tide. This rise in water level can cause severe flooding in coastal areas, particularly when the storm tide coincides with the normal high tides. Because much of the densely populated Atlantic and Gulf Coast coastlines lie less that 10 feet above mean sea level, the danger from storm tides is tremendous. Wave and current action associated with the tide also causes extensive damage. Water weighs approximately 1,700 pounds per cubic yard; extended pounding by frequent waves can demolish any structure not specifically designed to withstand these forces. The currents created by the tide combine with the action of the waves to severely erode beaches and coastal highways.
Storm Surge is an abnormal rise of sea level as the cyclone crosses the coast. Sea water inundates the coastal strip causing loss of life, large scale destruction to property & crop. Increased salinity in the soil over affected area makes the land unfit for agricultural use for two or three seasons. Storm surge depends on intensity of the cyclone (Maximum winds and lowest pressure associated with it and Coastal bathymetry (shallower coastline generates surges of greater heights).
A storm surge is a high flood of water caused by wind and low pressure, most commonly associated with hurricanes. The storm surge is the most deadly aspect of a hurricane, responsible for 90% of deaths during hurricanes. Storm surges are different from tidal surges, which are violent surges caused exclusively by the tidal shift in sea level. A storm surge is primarily caused by the extremely high winds which accompany a hurricane. This wind pushes the water rapidly, building it up into a huge wave. At the same time, the low pressure caused by a hurricane also causes the water level to rise up in the lowest-pressure spots and to sink in areas of higher pressure, exacerbating the wave buildup caused by the winds. Additionally, the shape of the ocean floor may affect how high the waves of the storm surge are when they reach land. It is not uncommon to see a storm surge in excess of 18 feet (6m), a wave that can potentially cause dramatic damage.
A storm surge occurs when powerful storm winds push water up onto the shoreline. This most frequently occurs when a hurricane makes landfall. Hurricanes are especially effective at producing a storm surge for these reasons: 1) Hurricanes have very poweful sustained winds that can reach over 100 miles per hour. These sustaned winds can push a lot of water towards the coastline. This water piles up, producing an elevated water level that is called a “storm surge”. 2) Hurricanes are low pressure storms and that low pressure causes a rise in sea level beneath the storm. 3) Hurricanes dump a lot of rain. That rain and its associated runoff can add to water levels in coastal areas. 4) If a hurricane makes landfall while the tide is rising both the tide and the wind working together can make an especially high storm surge. This is sometimes referred to as a “storm tide”.
