. . . An Unstoppable Wall of Water
Hurricane Storm Surge is the greatest threat to both life and property during a hurricane . . .it’s not just the wind that you need to worry about, but that great unstoppable moving wall of water which is being pushed across the land . . . that’s what causes many of the problems. Hurricane Katrina, for example, claimed at least 1500 lives, many of them either directly or indirectly because of the storm surge which accompanied it.
Storm Surge . . . Storm Tide . . . What Is It?
Hurricane Storm Surge is the rise of the water as a direct result of the storm, the amount which has increased over the general height of the tides. Storm tide, however, is the water level rise caused by a combination of the storm surge and the normal astronomical tide. The two added together . . . hence the storm tide . . . can cause phenomenal amounts of flooding in coastal regions, especially if the storm surge happens when there is a high tide. Storm tides can reach more than 20 feet in extreme cases . . . and there’s no stopping it.
Hurricane Storm Surges occur because of the water which is being pushed towards the shore by the sheer force of the winds moving around in the tropical storm. The low pressure which is associated with these intense storms is pretty minimal compared to the rate and strength of the water being pushed towards the coast by the wind.
Hurricane Storm Surges are very difficult to read and predict, because they are surprisingly sensitive beasts. Even a minimal change in the intensity of the storm, speed, radius, size, angle of approach to the land, central pressure plus the shape of the land it’s heading for can all have an effect on a hurricane storm surge. Estuaries and bays can make a big difference, for example, as well as the slope of the continental shelf in that region. A wide and shallow continental shelf, like the one found on areas of the Louisiana coastline might produce a massive storm surge of around 20 feet, but the same hurricane in a region with a very steep continental shelf (Miami Beach for example) might only product 8 feet of storm surge.
Hurricane Storm Surges can prove to be dangerous in different ways in different areas. Boats and marinas can be damaged in harbors due to a deadly combination of storm tides, currents and waves, and a storm surge in a estuary can kill vegetation and force alligators and snakes to flee from the flooded area causing yet another problem for a hurricane hit community, as well as the salt water intruding onto water supplies and endangering public health even further.
Major Hurricane Storm Surge Events
Hurricane Storm Surges have played a major part in the devastation caused by many hurricanes over the years. Hurricane Ike in 2008 had storm surges of around 15 to 20 feet higher than the normal tide levels, and Hurricane Katrina in 2005 was responsible for storm surges and flooding of between 25 and 28 feet. Other hurricanes of distinction in the storm surge department including Hurricane Dennis (2005), Hurricane Isabel (2003), Hurricane Opal (1995) and Hugo (1989).
Hurricane Storm Surge Facts – Do You Live In The Danger Zone
- Population density in Gulf coastal counties has increased by around 32% in just the last 20 years or so, with a 17% increase in Atlantic coastal counties and 16% in Hawaii. Yep, more and more people are living in areas which are high on the storm surge danger list.
- Many of the people who live in these densely populated areas live less than 10 feet above sea level . . . doesn’t sound good does it?
- Coastal zone areas are responsible for more than half of the nations productivity . . . there’s much more than lives and properties at stake then . . .
- A storm surge measuring, for example, 23 feet (which can and does happen) has the capabilities of inundating 67% of the interstates, nearly half of our rail miles, 57% of arterials, virtually all of the ports located along the Gulf coast area and 29 airports. That pretty much ties up everything then.