Tommorrow, Wednesday, August 11, 2021 at 2:20 p.m. EDT the Federal
Emergency Management Agency (FEMA) will be testing the national emergency
alert system and wireless emergency alert system.
Most of the news reporting has tried to simplify things.
The Wireless Emergency Alert (WEA) test on mobile devices is "opt-in."
By default, consumer devices are NOT enabled for WEA tests. A consumer
must manually enable test messages. Other emergency alerts are enabled by
default.
Instructions to enable/disable WEA test messages on iPhone and Android
https://www.fcc.gov/sites/default/files/weatest_opt-in_instructions.pdf
Additionally, only mobile devices with
1. WEA version 2.0 or later (roughly iPhone 6 and later)
2. Use a participating wireless service provider, the six major cellular
carriers covering 97% of subscribers participate in WEA
3. In range, and receiving a radio signal from a participating carrier
cell tower (not in a cave, basement, outback -- no signal)
4. Powered on, and not in airplane mode
You can provide feedback, if you opted-in, about how well the test worked.
FEMA-National-Test [@] fema.dhs.gov
https://www.fema.gov/fact-sheet/frequently-asked-questions-2021-ipaws-national-test