The work presented here enables us to numerically simulate ice accretion on transmission lines. Ice loads can cause significant damage to electric power transmission networks, especially in combination with wind. Overhead lines can collapse due to the mass of ice deposits, but also additional loads due to so-called Galloping oscillation can cause significant damage on the structures. Aerodynamic instability of cables due to ice accretion is a known phenomenon. Investigating shape and density of the ice accretion through experiments is very complex. Therefore, a numerical model is presented to simulate ice accretion processes on cables. The model is divided into two main parts, the calculation of the flow field and the ice accretion. The stream of air and precipitation particles is modelled as a one-way coupled multiphase flow. Ice accretion and flow field are calculated iteratively to account for geometrical changes of the ice deposit in the flow calculation. Finally, a risk management framework and its implications for power outages are investigated. Monetary losses due to blackouts increase exponentially with time. The presented approach evaluates variation in outage duration and compares the risk of blackouts to other types of disasters.