54th CMOS Congress Presentation: A new methodology for estimating historical snow loads for infrastructure design in Canada

A systematic reevaluation of ground snow loads over Canada has been performed using a methodology that improves upon previous National Building Code of Canada (NBCC) updates. Two independent sources of historical ground snow data were employed: the MSC (Meteorological Service of Canada) data set, consisting of daily snow depth (SD) measurements for 4412 stations, and the Manual Snow Survey data set, comprising snow water equivalent (SWE) data collected from 3320 locations, none exactly coincident with a MSC station. These extensive data along with a geographic snow climate classification scheme were used to develop power-law relationships between annual maximum SD and SWE over Canada, allowing the derivation of annual maximum SWE time series at each MSC station. After extensive quality control, an extreme value analysis was then applied to these time series to estimate the 50-year return level of annual maximum SWE and the corresponding snow load at over 500 MSC stations across Canada. Subsequent analysis of daily rainfall data resulted in the estimation of the 50-year return level of rain-on-snow loads at the same locations. A comparison of these results with those from the most recent NBCC (2015) exercise, which shows some systemic differences, will be presented. For example, although the medians are similar, the range of snow loads across Canada (0.4-20 kPa) is about twice that obtained in NBCC (2015).

This talk will be delivered by PCIC Senior Research Associate Charles Curry as part of the 54^th Congress of the the Canadian Meteorological and Oceanographic Society. CMOS is Canada’s national society of scientists, individuals and organizations involved in meteorology, oceanography and related fields, holds a national conference, showcasing research from the cutting edge of these disciplines. This year's Congress is being held online, with free registration.