Wireless Emergency Alerts (WEA) are designed to alert mobile users in the United States about missing children (also known as Amber Alerts), severe weather, and presidential announcements for national emergencies.
Alerts are geographically targeted, meaning you won't receive a notification for a missing child in San Francisco if you live in New York, and vice versa.
The system has proven to be helpful in warning people about dangerous situations, but alerts have also been known to reach phones at ungodly hours. And for some people, it might make sense to turn them off. For example, a person with multiple phones might want to opt out of the WEA system on one phone to avoid getting these alarms in stereo.
It only takes a few seconds to turn off Amber and weather alerts. But keep in mind, there's no way for you to disable or opt-out of.
The process to disable emergency alerts on an Android device will vary based on who makes the device and any customization done to the OS, but for the most part you should be able to locate the settings by searching for "Amber" or "Emergency" in the Settings app. Alternatively, the setting can be tucked into the Notifications section in the Settings app, under Advanced.
And on a Pixel 2 XL ($849 at Google Store) running Android 9.0 Pie, that's exactly where you'll find the various options to disable emergency alerts. Open the Settings app then go to Apps & notifications > Advanced > Emergency Alerts. There you'll find various settings and options available for you to customize how your device handles alerts.
Alerts can be turned off on an iOS device by opening Settings > Notifications. Scroll to the bottom of the page were you will be presented with an option to disable both Amber and emergency alerts.
Emergency alerts are also sent to basic mobile phones, more commonly referred to as feature phones. For those individuals who haven't yet upgraded to a smartphone, check with your wireless provider to see if they have any specific instructions to disable these alerts.
Update, Oct. 3, 2018, 11:36 a.m. Updated to include information about presidential alerts.