Americans: Today is FEMA Makes All Your Phones Ring Loudly Even If You've Set Them To Silent Mode Day, so if you've got a phone that should _not_ ring loudly for any reason you need to power it off by 2:00 Eastern, 11:00 Pacific at the latest and _leave it off until you can turn it on somewhere safe_. 

https://www.fema.gov/press-release/20230803/fema-and-fcc-plan-nationwide-emergency-alert-test-oct-4-2023