That is a good question since technically the Parkway winds around and East is not always East.  My opinion is it would be all the communities that are on the St Martins River then under Rt 90 including Terns , Pintail, Woodducks and down Manklin Creek. I also think the Point is included so pretty much, when entering the Northgate, every home on the water that is on your left. Hopefully common sense prevails and homeowners, based on experience, no matter where they are located on the water have an idea from past experience whether they should stick around.  

Just in case anyone is interested in what "mandatory evacuation" means;

In the United States a person cannot be forced to evacuate under most conditions. To facilitate voluntary compliance with mandatory evacuation orders first responders and disaster management officials have used creative techniques such as asking people for the names and contact of their next of kin, writing their Social Security Numbers on their limbs and torso so that their remains can be identified,[4] and refusing to provide government services in the affected area, including emergency services.