US: NWS Extreme and/or severe weather alerts on your phone.

[rcjordan]

BONUS: You can turn OFF those damn Amber Alerts!!

6. What types of WEA messages will the National Weather Service send?

   Tsunami Warnings (see Fact Sheet)
   Tornado and Flash Flood Warnings
   Hurricane, Typhoon, Dust Storm and Extreme Wind Warnings

8. Will I receive a WEA message if I'm visiting an area where I don't
live, or outside the area where my phone is registered?
Yes, if you have a WEA-capable phone and your wireless carrier
participates in the program. For information about which mobile
devices are WEA-capable and carrier participation, please visit
http://www.ctia.org/wea or contact your wireless carrier.

9. What if I travel into a threat area after a WEA message is already sent?
If you travel into a threat area after an alert is first sent, your
WEA-capable device will receive the message when you enter the area.

http://www.nws.noaa.gov/com/weatherreadynation/wea.html

For more details on WEA, including links to your wireless service
providers' unique WEA service information: www.ctia.org/wea

List of Carriers
http://www.ctia.org/your-wireless-life/consumer-tips/wireless-emergency-alerts

Example: Here are the instructions for a Verizon > Samsung Note 4
http://www.verizonwireless.com/support/knowledge-base-124081/