What Is a Storm Surge And What Causes It
Hurricanes and cyclones when hit the land, causes a great amount of damage ranging from destruction of houses to loosing of lives. They make several people homeless, destroy electrical supplies and create havoc on land. These monstrous storms causes continuous rise in seal level which is also known as storm surge. The creation of storm surge can easily be interpreted but the height of storm surge is dependent on several factors including physical characteristics of coastline to meteorological parameters of storm. Remember that almost 80 to 90 per cent of fatalities by hurricanes are resulted from storm surges.
Hurricane winds move in a circular pattern on water just like normal winds which causes waves on the beaches. However, hurricane winds are too powerful and travel with speed of 190 mph. In oceans, the water flows downhill but when it hits land, the wind piles water into a hill.
Coastline’s shape reflects the height of a storm surge. In case there is a shallow slope and broader continental shelf, it causes a larger surge. On the other hand, narrower continental shelf and steep slopes will result in a smaller surge. This is because water dissipates to greater degree here. Gulf Coast in the United States of America has shallower slopes as compared to other coastlines. Thus storm surges are expected to be larger here than in other coastal areas.
Besides storm surge, tidal factors are directly related to the amount of damage inflicted. They combine with storm surge in order to make an overall storm tide. Remember that high tides increases storm surge whereas low tides reduce it. When combined with storm surge, storm tides can reach 20 to 30 feet.
As storm surge is created when wind forces water towards the shore. Lower pressure of winds will cause less damage and storm surge. However, research show that if the wind speed is double, the storm surge can be doubled as well.
Parameters of storm can affect storm surge. The intensity of storm affects radius of maximum winds and eventually affect storm surge. Forward speed of storm is one of the main factors which affect a storm surge. If the forward speed is 18 to 20 mph, storm surge produced will be greatest. A storm which moves in the direction which is perpendicular to coastline, storm surge produced will be greatest.