The topic of this contribution is the investigation in quantitative terms of Offshore Wind Farm (OWF) disturbances due to cyber-attacks, physical attacks and natural causes leading to high-impact low-probability events. The impact of these disturbances was quantified with simulation models of OWFs and identified as service interruption and damage. Critical characteristics of these disturbances were determined by which a disturbance at wind turbine scale results in a disruption at OWF scale as a cascading/snowball effect. Accordingly, the results provide the quantitative signatures of the disturbances which are useful for the improvement of the OWF systems design and operation.