Decision Support Systems help human operators to cope with large amount of information and make decisions. However, in complex dynamic environments, automation can create different types of uncertainties in the system, and consequently, in the mind of the operator. A comprehensive understanding of the types of uncertainties in complex environments and their impact on human decision-making is essential for designing safe and efficient systems. In this paper, we analyze and identify different types of uncertainties that could surface during human-automation interaction. We will consider the problem of uncertainty from the human factor perspective and propose guidelines for designing systems that will support human operators in performing their tasks efficiently while coping with uncertainties.