The Office of Emergency Management works to prepare plans, policies, and procedures for city operations when responding to and mitigating against natural or man-made disasters. They also help lead the response during and after emergencies, often in coordination with public safety officials, elected officials, nonprofit organizations, and government agencies.
The Virginia Department of Emergency (VDEM) Management has a great resource to help understand when to evacuate during a storm. Download the information from VDEM's Know Your Zone site.