Merge pull request #111344 from mrbullwinkle/mrb_04_13_2020_availability_state_based

state based alerts

Author: PRMerger20

articles/azure-monitor/app/availability-alerts.md

@@ -30,6 +30,9 @@ Alerts are now automatically enabled by default, but in order to fully configure
 
    ![Edit after save](./media/availability-alerts/set-action-group.png)
 
+> [!NOTE]
+> Availability alerts created through this experience are state-based. This means that when the alert criteria is met a single alert is generated when the site is detected as unavailable. If the site is still down the next time the alert criteria is evaluated this won't generate a new alert. So if your site was down for an hour and you had setup an e-mail alert, you would only receive an e-mail when the site went down, and a subsequent e-mail when the site was back up. You would not receive continuous alerts reminding you that the site was still unavailable.
+
 ### Alert on X out of Y locations reporting failures
 
 The X out of Y locations alert rule is enabled by default in the [new unified alerts experience](https://docs.microsoft.com/azure/monitoring-and-diagnostics/monitoring-overview-unified-alerts), when you create a new availability test. You can opt out by selecting the "classic" option or choosing to disable the alert rule.