Freezing rain is a climate-related risk that’s emblematic of Quebec; just think of the ice storm in 1998 that plunged a good part of the province into darkness for weeks. Despite its prevalence and its potential impacts, modelling freezing rain is a significant challenge for scientists. It has been difficult to reconstruct the past and simulate the future of freezing rain in Quebec.
Climate models are unable to accurately represent this complex phenomenon, and the lack of detailed data considerably limits the precision of these models.
Improving projections of freezing rain
For several years, Ouranos and its partners have been working jointly on research projects that have led to significant advances in the field, providing useful information on the changes in freezing rain and how to model them. The production of this data required several complex scientific steps:
Evaluation of the ability of the Canadian Regional Climate Model (CRCM5) to simulate freezing rain
Simulation of freezing rain with a resolution of tens of kilometres, generated by combining information on the atmospheric circulation conditions conducive to freezing rain in the St. Lawrence Valley with a model-based reproduction of certain past episodes
Analysis of the main sources of uncertainty that can influence the frequency of freezing rain in climate simulations
A key learning is that the planetary model driving the CRCM5, as well as the diagnostic methods, are very important
Production of a dataset describing the expected future changes in freezing rain for North America.
New tools developed by Ouranos
Based on these scientific and technical advances, Ouranos recently published a summary of knowledge on the changes in freezing rain in Quebec. This was possible thanks to its access to complex data, allowing for a more precise assessment of climate risks at a local scale.
In close collaboration with infrastructure and transportation experts, Ouranos has also enhanced the Climate Portraits platform by adding new indicators dealing with freezing rain, in response to the growing demand from the various stakeholders concerned. This valuable data will enable better understanding of this issue and help develop more effective adaptation strategies.
Three freezing rain indices are available on Climate Portraits:
Hours of freezing rain: the annual number of hours of freezing rain
Long-duration freezing rain events: the annual number of long-duration freezing rain events (greater than or equal to 6 hours)
Intense freezing rain events: the annual number of episodes with at least 10 millimetres of freezing rain
Collective expertise
Filling in the gaps in the knowledge on freezing rain required ten years of collaborative work between Ouranos and the Université du Québec à Montréal.
The involvement of the two institutions made it possible to:
Improve the spatial and temporal resolution of regional climate models to better estimate the frequency and severity of freezing rain events, which occur over short periods of time and can vary considerably over short distances
Develop diagnostic methods to quantify future snow, rain, freezing rain and sleet events using regional models
Develop and operationalize a freezing rain analysis chain in regional climate models
This initiative clearly illustrates Ouranos’ role in the combatting climate change. As a boundary organization, the consortium develops knowledge on climate change by working with a wide variety of experts to provide operational data to users.
This data, arising from collective expertise, is invaluable in supporting decision-making and strengthening the resilience of our communities and our industries.
