Summary Report Completed in Dec. 2001
Mississippi Hurricane Evacuation Study

The primary study area for the Mississippi HES is Hancock, Harrison  and Jackson Counties.  Click on the adjacent small map to view a larger map of the area.  Hit the Back Button to return to this page.

Hurricane Surge/SLOSH  -   The Mississippi Sound  SLOSH Model was completed by the National Hurricane Center in June 1999.   Click on the picture below to see a larger view.  The grid is a telescoping hyperbolic coordinate system with 115 arc lengths and 68 radials.  The smallest grid represents an area of about 0.01 square miles.  This permits inclusion of topographic details such as highway and railroad embankments, causeways, levees, etc.  The largest grid cell is about 14 square miles.  A total of 2445 hypothetical hurricanes were run through the Mississippi Sound SLOSH Model to determine the worst case surge elevation for each of the five hurricane categories.   These maximum water surface elevations were converted to water surface grids which were used to develop surge flood maps.   Click on the following SLOSH button to view detailed documentation on the Mississippi Sound SLOSH model.   In PDF format.

Other SLOSH basins in the U.S. can be seen by clicking. 

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Surge Maps

The surge maps for Mississippi Coastal Counties were developed by overlaying the water surface grid from the SLOSH model on a ground elevation grid made from USGS 7.5 minute DEM's and determining which ground cells were flooded.    Surge maps for the Counties can be viewed by clicking the Maps Button on the HES Home Page.  

Evacuation Zones

The surge areas were used to determine evacuation zones.  The three coastal counties in Mississippi created three evacuation zones and called them A, B and C.   The zones generally correspond to the Category 1-2 storms of Zone A, Category 3 for Zone B and Category 4-5 for Zone C.   The evacuation zone maps can be viewed by selecting the Maps Button on the HES Home Page.

Evacuation Routes

The primary hurricane evacuation routes for the three coastal counties can be viewed by selecting the Maps Button on the HES Home Page or by clicking one of the following county names, Hancock, Harrison or Jackson.

Vulnerability Analysis

The primary purpose of the vulnerability analysis is to identify the areas and populations that are vulnerable to storm surge and to wind damage.   The following table shows the vulnerable population by dwelling unit for the various evacuation zones.  
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Behavioral Studies  -  Hundreds of telephone interviews have been made in Mississippi to determine how people react to hurricane threats and evacuation orders.   These statistical studies are used to estimate how many people will evacuate, where they are headed, and what type of shelter they plan to use.   These studies help to determine the amount of time that is necessary to get all evacuees off the roads and to safety before gale force winds hit the coast.    This behavioral study report and all detailed data tables of this study effort can be viewed by clicking the following button.    In PDF format.

Transportation Studies - During a hurricane evacuation in Mississippi significant numbers of vehicles have to be moved on the roadway network in a relatively short period of time.  With limited sheltering available for a major hurricane in the coastal counties, most evacuees go to inland counties and beyond to seek shelter.  This often creates traffic backups and long travel times.

The transportation study determines how many vehicles will leave each evacuation zone, what roads they will most likely use and how long it will take them to get to safety before gale force winds hit the coast.   This length of time is called a clearance time and helps the Counties decide when they need to order an evacuation to insure all evacuees can get to safety and avoid hazardous weather conditions.

The following Tables shows the estimated number of vehicles evacuating to shelters, friends & relatives, motels and out-of-county, by hurricane category and ranges of clearance times.   You can review the entire transportation report by clicking on the following button.  In PDF format.

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Evacuating Vehicle Table

Clearance Time Table

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SHELTER DATA

All three coastal counties use mostly public schools for hurricane shelters.   The counties have made every effort to provide sufficient shelter space for expected evacuees.  However, Category 3,4 and five storms threaten many of these shelters and they can not be used so available shelter space decreases as the hurricane strength increases.  It is very important to listen to your local emergency management office if you are considering going to a local public shelter to confirm the shelter will be open.

If you plan to seek a hotel or motel in Mississippi you will what to be sure to make reservations early.   Motel rooms tend to fill up quickly when a hurricane is in the Gulf.  A map of the number of hotel rooms by County can be viewed for the state of Mississippi by clicking on the Maps button on the HES Home Page.