Severity and return periods of icing events in the Montréal area

A Markov Chain model based on hourly surface weather observations is used to estimate the return period of severe icing events. A severe icing event for this study was considered to be one for which the force due to wind on accumulated ice on a 25 mm diameter cable exceeds 10 N/m. Results of the analysis suggest that the return period of such an event is every 32 years on average for the Montréal area. Other simulations were conducted to estimate the return periods based on hypothetical future scenarios in which the probability of occurrence of freezing precipitation is higher.