Many hospitals used to develop specific plans for a variety of disaster and emergency situations. The Federal Emergency Management Agency (FEMA) now requires that hospitals use an emergency management system that is comprehensive, risk based, and all-hazard in nature. All-hazard planning is based on a general plan that works for many different emergency/disaster presentations, with incident specific responses found in annexes to the general plan. Hazard Vulnerability Analysis (HVA) ranks the likelihood and severity of the possible hazards occurring for the hospital and/or the Operational Area, and gives planners the ability to plan for the events posing the greatest threat.