  Reliable functioning of infrastructure networks is essential for our modern
society. Cascading failures are the cause of most large-scale network outages.
Although cascading failures often exhibit dynamical transients, the modeling of
cascades has so far mainly focused on the analysis of sequences of steady
states. In this article, we focus on electrical transmission networks and
introduce a framework that takes into account both the event-based nature of
cascades and the essentials of the network dynamics. We find that transients of
the order of seconds in the flows of a power grid play a crucial role in the
emergence of collective behaviors. We finally propose a forecasting method to
identify critical lines and components in advance or during operation. Overall,
our work highlights the relevance of dynamically induced failures on the
synchronization dynamics of national power grids of different European
countries and provides methods to predict and model cascading failures.
