Those are messages or emaill that you get when the event that is being monitored has occurred.

Use these settings to manage your emergency alerts. The options are:
• Emergency alerts: Choose from All alerts on, Extreme alerts only, or Presidential alerts only.
• AMBER alert: Choose Onto receive Amber alerts.
• Reminder: Set how you want to be reminded about alerts: Once, Every 2 minutes, Every 15 minutes, or Off.