Wind turbines operate under large and continuous fluctuation of wind conditions, and their rotors undergo real-time adaptation that try to accommodate these changes while maintaining safety and efficiency. Therefore, studying the dynamic behavior of rotor blades is key for the validation of design assumptions and for the optimization of performance and durability. As a non-destructive and cost-effective approach, Operational Modal Analysis (OMA) is generally a practical and effective solution for the study of structures without disturbing their normal operation, which is particularly relevant in the case of wind turbines, given their main purpose of power production. In this context, this work introduces the dynamic monitoring system installed in the rotor of an onshore wind turbine in Portugal, and the experimental data used to identify the modal properties of the rotor blades under parked conditions, being supported by results obtained from a numerical model of the entire structure.