While storm surge is water that is pushed onto shore by a hurricane, it is rarely seen as a “wall of water.” More commonly, storm surge is experienced as a rapid rise in the water level – as fast as several feet in just a few minutes. A cubic yard of sea water weighs in at more than 1,700 pounds – almost a ton – and is propelled by the forward speed of the hurricane (typically 10 to 15 mph). Standing in storm surge as shallow as six inches can be challenging, and a one-foot deep storm surge exerts enough power to sweep a car off the road. Compounding the destructive power of the rushing water is the large amount of floating debris that typically accompanies the surge. Trees, pieces of buildings, and other debris float on top of the storm surge and act as battering rams against anything unfortunate enough to stand in the way.
While storm surge is commonly considered the most dangerous part of a hurricane, inland flooding also poses a major threat. Inland flooding has been responsible for more than half of hurricane related deaths. From 1970 to 1999, one quarter of inland flooding deaths claimed lives by drowning inside vehicles as just two feet of water can drift a vehicle.
Hurricanes are capable of producing as much as 5 to 10 inches of rain, and in some cases, more than 20 inches of rain. In these situations, storm drains cannot handle the amount of water and can quickly become clogged with debris, causing rapid and dangerous rise in water levels.