A civil emergency message (SAME code: CEM) is a warning issued through the Emergency Alert System (EAS) in the United States to warn the public of a significant in-progress or imminent threat or danger to public safety.
It is typically issued by a local or state authority and is relayed by the National Weather Service.
The warning is a higher priority than a local area emergency (LAE), but it's less specific than a civil danger warning (CDW).
For example, the warning could be used to describe an alert issued by the National Terrorism Advisory System.
A mandatory evacuation of portions of McDowell County, North Carolina issued after a landslide, caused by the effects of Tropical Storm Alberto, threatened the integrity of a dam in the county: [1] This article incorporates public domain material from Non-weather Related Emergency Message Description Guidelines (PDF).