NWS LIX - Hurricane Storm Surge Threats and Impacts

EXTREME

Potential for inundation of 7 feet or greater above ground

DEVASTATING TO CATASTROPHIC

         Potential Impacts:  There is an extreme threat to life and property.   

* Prepare for the likelihood of extreme storm surge damage.  Residents should take immediate action to protect life and heed evacuation advice from emergency management.

* Thousands of homes and vehicles will be flooded. Larger structures such as condominiums and hotels may be destroyed. 

* People not heeding evacuation orders in single family, one or two story homes could face certain death.

* People in the storm surge zone who have not evacuated should seek shelter in the nearest well built multi story building if possible. If evacuating to the attic take along a life jacket and ax to chop through the roof in the event severe flooding occurs.

* Coastal residents in multi story facilities risk being cutoff for a week or more.

* Significant storm surge flooding will move well inland especially along bays and bayous.

* Many residences of average construction directly on the coast will be destroyed.

* Significant storm surge flooding will move well inland especially along bays and bayous.

* Numerous roads will be swamped. Some may be washed away by the water.  Entire flood prone coastal communities will be cutoff, perhaps for more than a week. 

* Southeast Louisiana -7 to 15 foot inundation:  Life threatening flooding possible in areas outside hurricane protection levees and in areas around Lakes Pontchartrain and Maurepas. 

* Sections of west Jefferson, east St Charles and lower Lafourche hurricane protection levees could be over topped.  Water levels may exceed 7 feet or more behind over topped levees.

 * Coastal Mississippi – 7 to 15 foot inundation:  Life threatening flooding possible in coastal areas and along bays and coastal bayous.

* Southeast Louisiana - 15 to 20 feet or greater inundation:  Life threatening flooding is likely with deep and widespread storm surge flooding across many areas.

* Hurricane protection levees in southeast Louisiana will be over topped with potential of massive and widespread flooding. 

* Severe flooding will occur around Lakes Pontchatrain and Maurepas impacting many communities near the lakes with deep flooding.

* Water levels may exceed 15 feet or more behind over topped levees for several weeks. Full recovery will take months if not years.

* People who fail to evacuate may be swept to their deaths while others may be stranded for days surrounded by flood waters. Dozens of roads will be washed away.

* Coastal Mississippi - 15 to 20 feet or greater inundation:   Life threatening flooding is likely with deep and widespread storm surge flooding across many areas. 

* Storm surge and waves will pound the Mississippi coast with storm surge moving well inland, especially along bays, bayous and rivers. 

* Thousands of homes and vehicles will be flooded. Larger structures such as condominiums and hotels may be destroyed.  Those with poor support may collapse. 

* Persons in the storm surge zone who fail to evacuate may be swept to their deaths while others may be stranded for days surrounded by flood waters. Full recovery will take months if not years.   

HIGH

Potential for inundation 5-7 feet above ground

EXTENSIVE

  Potential Impacts:  There is a critical threat to life and property.  Significant storm surge flooding will move well inland especially along bays and bayous.

* Coastal residents of one story homes in the storm surge zone who do not evacuate will face life threatening  consequences;  those in multi story or multi unit facilities risk being cut off for days.

* People not heeding evacuation orders in single family one or two story homes in the storm surge zone could face certain death.

* Numerous roads will be swamped. Some may be washed away by the water. 

* Entire flood prone coastal communities will be cutoff, perhaps for more than a week. 

* Southeast Louisiana - 5 to 7 feet inundation:  Life threatening flooding possible in areas outside hurricane protection levees and in areas around Lakes Pontchartrain and Maurepas. 

* Sections of west Jefferson and lower Lafourche hurricane protection levees could be over topped.    

* Coastal Mississippi – 5 to 7 feet inundation: Life threatening flooding possible in coastal areas and along bays and coastal bayous.  

MODERATE

Potential for inundation 3-5 feet above ground

SIGNIFICANT

  Potential Impacts:  There is a significant threat to life and property

For 3 to 5 foot inundation:  Storm surge flooding can be expected outside hurricane protection levees, in areas around Lakes Pontchartrain and Maurepas and along the immediate Mississippi coast and bays.

* Flooding of several feet of water will occur in non elevated structures or those built on slabs, causing damage. Roads along the coast, bayous, bays and low lying areas will be impassable 

ELEVATED

Potential for inundation 1-3 feet above ground

LIMITED

  Potential Impacts: There is an elevated threat to life and property.

For 1 to 3 feet inundation:  Minor storm surge flooding can be expected outside of hurricane protection levees, in areas around Lakes Pontchartrain and Maurepas and along the immediate Mississippi coast and bays.

* Some non elevated homes in these areas may experience flooding. Minor tidal flooding of property and some flooding of low lying roads may occur.

NONE 

Little to no inundation

NONE

 Potential  Impacts:  No discernible threat to life and property. No storm surge expected. Coastal flooding is not expected.