Snow Loads in Norway, 1961-2020

Snow loads are an important consideration in the design of buildings. Particularly in parts of Norway where heavy snowfall is common, it is important to know the weight from snow on houses to avoid structural damage or collapse. National standards and building regulations have been focusing on snow loads since 1949, and these regulations have been revised several times. 

 

The Norwegian Meteorological Institute (MET Norway) produces daily interpolated data sets of precipitation and temperature with a 1*1 km resolution as part of our regular service. Data from 1957 - dd are included. These data sets are then used by the Norwegian Water Resources and Energy Directorate (NVE) to generate "Snow Water Equivalent" (SWE) interpolated data sets, grids, using a hydrological model. 

 

In this study, the SWE grids are  used to produce snow loads with a 50 year return period for Norway, for two different periods 1961-1990 and 1991-2020. Three different methods for calculating the 50-year return period of snow loads are compared. In addition, the old normal period, 1961-1990, is compared with the current normal period, 1991-2020. It is typically shown that the snow load decreases in the lower-lying areas and along the coast of Norway. In higher altitude areas and in parts of Northern Norway, where there still are cold winters, the snow loads have increased. 

 

Snow loads are also extracted for each municipality center in Norway, to compare to the current national snow loads standard. This method is suggested, and about to be adopted, for future use in the design of buildings in Norway.