It is marvellous that in Australia we get bushfire alerts on our mobile phones, if we are located somewhere at risk. Unfortunately this will not work if cell towers are not functioning.
In Chile, people can receive emergency updates without any connection to a mobile phone or internet service.
It is received on your phone, via radio transmission.
This seems to be a very affordable way of making sure that every possibility is covered in keeping people safe.
More here:
http://www.sieapp.cl/en/