On extreme ground snow depth and ground snow load at Canadian sites

Abstract

The roof snow load in the National Building Code of Canada (NBCC) is expressed as the sum of the snow and rain components. A probabilistic analysis of the components was carried out by using the recorded historical meteorological data. Probabilistic characterizations of the annual maximum ground snow depth SA, ground snow load SL, and snowpack bulk density were given. By considering the commonly adopted probabilistic models for SA, it was found that the use of the lognormal distribution, Gumbel distribution, and generalized extreme value distribution (GEVD) for SA is preferred for 46%, 35%, and 19% of the considered meteorological stations. A similar observation was made for SL. Snow hazard maps in terms of return period values of SA and SL were developed. Also, the hazard maps of (winter) rain load, SR, were developed. It was found that the correlation coefficient between SA and SR is negligible; the implication of this is discussed.