Abstract: The present disclosure relates to methods (400, 500) for reducing vibrations in parked wind turbines (10), assemblies (82) comprising vibration mitigating devices (300) for wind turbine blades (22) and wind turbines (10). An assembly (82) comprises a vibration mitigating device (300) configured to be arranged around a wind turbine blade (22) of a wind turbine (10) and comprising one or more inflatable bodies (305) and one or more air flow modifying elements (310); and a pressure source (98) configured to inflate and/or deflate one or more of the one or more inflatable bodies (305) based on measurements of a sensor system (97) configured to monitor the wind turbine (10) and/or environmental conditions around the wind turbine (10).