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Evacuation Information EVACUATION LEVELS AND TYPES OF STORMS
Levels and Types of Storms
The threat of deadly storm surge, fresh water flooding and damaging winds caused by a hurricane requires that all persons in a Hurricane Warning area be prepared to seek suitable shelter and take other protective actions in sufficient time to escape the ravaging effects of the storm. Because Chatham County is coastal, low-lying and particularly susceptible to the full fury of a hurricane the evacuation of its citizens from high risk areas will often be a necessity. The actual number of people who need to evacuate and the distances they should travel will be determined by the severity of the
storm itself.
In Chatham County there are basically two levels of evacuation appropriate for hurricane conditions; "Partial" and "Full", depending on the severity of the storm:
Under a PARTIAL Evacuation, the following areas would be affected:
All islands (not just "barrier islands")
All waterfront properties (including rivers, creeks, canals)
All low lying areas adjacent to marshes, wetlands, etc.
All flood prone areas (including rainfall flooding)
All mobile/manufactured type parks and homes of unsturdy construction
Under a FULL Evacuation, the following areas would be affected:
Entire County (No exceptions for the general public).
From these two levels of evacuation, two types of evacuation may be come necessary depending on the severity of the Storm; namely "Voluntary" and "Mandatory":
Under a VOLUNTARY Evacuation:
Government officials strongly urge and recommend persons in designated evacuation areas to relocate to safer locations for their own safety. Personal discretion allowed, but not advised.
Under a MANDATORY Evacuation:
Government officials order all persons in designated evacuation areas to relocate to safer locations for their own safety. Personal discretion not to be a deciding factor. A mandatory evacuation order will apply to the public in general. Exceptions would include public safety officials, disaster response personnel and organizational, agency, business employees designated as "critical workforce" or "essential". However, all of these individuals will be expected to eventually seek adequate shelter prior to the onset of hurricane conditions. Persons who refuse to comply with a mandatory evacuation order will not be arrested nor forcibly removed from their homes. However they should not expect rescue or other lifesaving assistance after the onset of gale force winds. ( The same will hold true for persons ignoring a voluntary evacuation order.)
Each storm threat will dictate its own combination of levels and types of evacuations to be authorized by government officials:
For Categories 1-2 storms, either a Voluntary Full or a Mandatory Partial evacuation will be issued. For Category 3-5 storms, only a Mandatory Full Evacuation will be issued.
Time Frames Necessary to Evacuate (Clearance Times)
There are two critical factors in the decision making process in recommending or ordering evacuation: The first being the time necessary to clear evacuees from the evacuation area (i.e., the clearance time which is defined as the time required to clear the roadways of all vehicles evacuating). The second is weighing the clearance time in respect to the arrival time of hurricane pre-landfall hazards.
Clearance time begins when the first vehicle enters the evacuation route network and ends when the last vehicle reaches a local shelter or the County line on the way to inland shelter. The clearance time is developed to include the time required for evacuees to secure their homes and prepare to leave, the time spent by all vehicles traveling along the evacuation route network and the additional time spent on the road caused by traffic and road congestion. Clearance time does not relate to the time any one vehicle spends traveling along the evacuation route network. It also does not guarantee vehicles will safely reach their destination once outside the County.
Evacuation should be completed prior to the arrival of sustained 34 knot (gale force) winds or the onset of storm surge inundation whichever occurs first. Based on a storm with a radius of 100 miles, moving at 10 miles per hour, this could reduce the evacuation time for a projected landfall at 24 hours to only 14 hours. In Georgia the primary limiting factor for hurricane evacuation is the arrival time of sustained 34 knot winds, ( which convert to 39 miles per hour).
It is critical for decision makers to understand that H1 projections for landfall refer to the eye of the storm passing over the shoreline. Gale force winds may extend 100-200 miles ahead of the eye. These winds will only increase as the storm approaches and could last for 6-12 hours (or more), accompanied by rapidly deteriorating conditions (e.g., traffic hazards, torrential rain, storm surge and fresh water flooding).
Once gale force winds arrive it will become increasingly unsafe to be outdoors, particularly on the roads. Therefore any evacuation orders in effect will be canceled (or terminated) at that point. Persons who have not yet begun evacuating will be told that it is too late to try and that they should either stay where they are or else go immediately to a nearby refuge (discussed later in this plan). Clearance time is primarily calculated on the basis of:
Number of people evacuating (including tourists)
Number of vehicles on roadways
Number and capacity of evacuation roadways
Potential roadway choke points or bottlenecks
Time of day
Response time for evacuees after orders are issued
