Solarwinds HA logs an event with EventType 6500 when a failover event occurs. This event should be associated with a Solarwinds entity so that it can trigger Solarwinds alerts.
Right now, HA can send email when an HA pool member changes state. This is nice, but it can't be used to automate other actions. For example, I want to manage and unmanage certain application monitors on my HA pool members depending on whether they're active or standby. This would be easy to do using an alert action.