Disaster 114 : A sudden unplanned event that causes great damage and/or serious loss. (PCiCCDE); A calamitous (great misfortune) event, especially one occurring suddenly and causing great damage. (Webster)
Arizona Department of Health Services, Emergency Preparedness Glossary, Phoenix, Arizona, USA 2011. http://www.azdhs.gov/als/childcare/documents/prepa redness/emergency-preparedness-glossary.pdf, (Emr Prep - Amer) {846}