Alerts in vRealize Operations Cloud are of three types. The alert type determines the severity of the problem.

Health Alerts
The health alert list is all the generated alerts that are configured to affect the health of your environment and require immediate attention. You use the health alert list to evaluate, prioritize, and immediately begin resolving the problems.
Risk Alerts
The risk alerts list is all the generated alerts that are configured to indicate risk in your environment. Address risk alerts in the near future, before the triggering symptoms that generated the alert negatively affect the health of your environment.
Efficiency Alerts
The efficiency alerts list is all the generated alerts that are configured to indicate problems with the efficient use of your monitored objects in your environment. Address efficiency alerts to reclaim wasted space or to improve the performance of objects in your environment.