Wireless Emergency Alerts (WEA), also known as CMAS, is a part of a national alerting system called IPAWS (Integrated Public Alert and Warning System) that enables emergency management officials to rapidly disseminate the warnings and safety information via text alerts to wireless phones based on the phones’ geographic location.
The Federal Emergency Management Agency or FEMA is responsible for receiving the alerting information and forwarding the alerts to participating wireless carriers such as Sprint. Such alerts may come from the President of the United States; the National Weather Service, state or county public safety officials. This system is integrated into the same national alerting services that serve television and radio today.
For more information regarding WEA/CMAS please go to FEMA website.