47 CFR § 10.400 - Classification.
A Participating CMS Provider is required to receive and transmit four classes of Alert Messages: Presidential Alert; Imminent Threat Alert; Child Abduction Emergency/AMBER Alert; and Public Safety Message.
(a) Presidential Alert. A Presidential Alert is an alert issued by the President of the United States or the President's authorized designee.
(b) Imminent Threat Alert. An Imminent Threat Alert is an alert that meets a minimum value for each of three CAP elements: Urgency, Severity, and Certainty.
(1) Urgency. The CAP Urgency element must be either Immediate (i.e., responsive action should be taken immediately) or Expected (i.e., responsive action should be taken soon, within the next hour).
(2) Severity. The CAP Severity element must be either Extreme (i.e., an extraordinary threat to life or property) or Severe (i.e., a significant threat to life or property).
(3) Certainty. The CAP Certainty element must be either Observed (i.e., determined to have occurred or to be ongoing) or Likely (i.e., has a probability of greater than 50 percent).
(c) Child Abduction Emergency/AMBER Alert.
(1) An AMBER Alert is an alert initiated by a local government official based on the U.S. Department of Justice's five criteria that should be met before an alert is activated:
(i) Law enforcement confirms a child has been abducted;
(ii) The child is 17 years or younger;
(iii) Law enforcement believes the child is in imminent danger of serious bodily harm or death;
(iv) There is enough descriptive information about the victim and the abduction to believe an immediate broadcast alert will help; and
(v) The child's name and other data have been entered into the National Crime Information Center.
(2) There are four types of AMBER Alerts: Family Abduction; Non-family Abduction; Lost, Injured or Otherwise Missing; and Endangered Runaway.
(i) Family Abduction. A Family Abduction (FA) alert involves an abductor who is a family member of the abducted child such as a parent, aunt, grandfather, or stepfather.
(ii) Nonfamily Abduction. A Nonfamily Abduction (NFA) alert involves an abductor unrelated to the abducted child, either someone unknown to the child and/or the child's family or an acquaintance/friend of the child and/or the child's family.
(iii) Lost, Injured, or Otherwise Missing. A Lost, Injured, or Otherwise Missing (LIM) alert involves a case where the circumstances of the child's disappearance are unknown.
(iv) Endangered Runaway. An Endangered Runaway (ERU) alert involves a missing child who is believed to have run away and in imminent danger.
(d) Public Safety Message. A Public Safety Message is an essential public safety advisory that prescribes one or more actions likely to save lives and/or safeguard property during an emergency. A Public Safety Message may only be issued in connection with an Alert Message classified in paragraphs (a), (b) or (c) of this section.