Nixle: Alert Message CAP Fields & IPAWS


What are the fields that show when I create a Nixle alert message?

Must the fields be completed to send out my Nixle alert message?

What is the Integrated Public Alert & Warning System (IPAWS)?


  • Alert messages should only be used for the most critical and time sensitive information.
  • To avoid confusing your residents, choose to checkmark the System Test option if your alert message will be sent as a system test.
CAP Alert Message Fields


When a Nixle alert message is created, the Common Alerting Protocol (CAP) requires that the message be consistently disseminated simultaneously over many warning systems to many applications. The Nixle alert message meets those requirements when you specify the following fields:

  • Category
  • Event
  • Severity
  • Urgency
  • Certainty


The category field denotes the type of alert being entered. Some examples of alert types are:

  • general emergency and public safety
  • flood, fire or landslide
  • chemical, biological, radiological threat or attack


The event field helps clarify the category type and quickly summarizes the subject of your alert. Some examples of event specification are:

  • An alert with a category of rescue and recovery and a mountain rescue event.
  • An alert with a category of medical and public health and a foodborne disease outbreak event.
  • An alert with a category of public and private transportation and a train derailment event.


The severity field indicates the bodily injury risk level associated with your alert. The severity levels are as follows:

  • Extreme: extraordinary threat to life or property.
  • Severe: significant threat to life or property.
  • Moderate: possible threat to life or property.
  • Minor: minimal to no known threat to life or property.
  • Unknown: the severity is unknown.


The urgency field indicates how quickly your residents should take action upon receiving your alert. The urgency levels are as follows:

  • Immediate: responsive action should be taken immediately.
  • Expected: responsive action should be taken within the next hour.
  • Future: responsive action should be taken in the near future.
  • Past: responsive action is no longer required.
  • Unknown: the urgency is unknown.


The certainty field informs your residents if the alert is currently occurring or likely to occur in the future. The certainty levels are as follows:

  • Observed: the alert is determined to have occurred or is ongoing.
  • Likely: the probability of the alert occurring is greater than 50%.
  • Possible: the probability of the alert occurring is less than 50%.
  • Unlikely: the probability of the alert occurring is approximately 0%.
  • Unknown: the probability of the alert occurring is unknown.


Qualifying agencies can author and send geographically targeted alert messages via the Federal Emergency Management Agency's (FEMA) Integrated Public Alert & Warning System (IPAWS). IPAWS encompasses multiple alert networks including the Wireless Emergency Alerts (WEA) and the Emergency Alert System (EAS) and others that use Common Alerting Protocol (CAP) standards with the IPAWS infrastructure. IPAWS is a modernization and integration of the nation's alert and warning infrastructure and will save time when time matters most, protecting life and property.

To learn more about IPAWS, please visit their website at If you are interested in learning how your agency can use IPAWS with your alert messages, please send an email to

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