Types of Loads

Snow load generally affects the roof and greatly depends on the building location. It also depends on the roof geometry as snow can accumulate within the valleys of curved roofs and slides from the steep areas. Local exposure of the structure can be another factor as the snow in the wide-open areas can easily melt under direct sunlight or be blown away by wind.

Roof Snow Load

One major aspect of design of structures subjected to snow, wind and earthquake loads is the consideration of larger applied loads for more important structures. This affects buildings where failure may result in large loss of lives or buildings that may be required to be operational in case of an emergency such as a police station, hospital, etc. This is generally accomplished by building codes through the use of an “importance factor” for the computation of design snow load.

Snow drift can happen when two adjacent buildings have different roof elevations or there is a large change in the building roof height. When wind blows, it can drift snow over the lower level roof or accumulates snow along the boundaries of the lower and upper roofs.

Snow Drift on a Roof

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