The interconnected European Electricity Markets see considerable cross-border trade between different countries. In conjunction with the structure and technical characteristics of the power grid and its operating rules, the corresponding commercial flows translate into actual physical flows on the interconnection lines. From the interplay of different physical, technical, and economic factors thus emerge complex spatiotemporal power flow patterns. Using Principal Component Analysis, in this contribution hourly time-series of cross-border physical flows between European countries in 2017 and 2018 are analyzed. The most important patterns in the time series of imports/exports and cross-border physical flows are identified. Their spatial and temporal structure, as well as their contribution to the overall variance is described. Additionally, we apply a tracing technique to the overall flow patterns, which allows identifying the physical power transfers between European countries through the common grid infrastructure.