Sliding Snow On Sloping Roofs

This digest discusses the mechanisms and forces involved when snow slides down smooth metal or glass roofs and shows how to compute the forces that sliding snow imposes on chimneys parapets and snow fences.

Sliding snow on sloping roofs.

P s c s p f. The sloped roof snow load p s shall be obtained by multiplying the flat roof snow load p f by the roof slope factor c s. They must be able to carry substantial snow loads 1 3 but the possibility also exists of the snow suddenly breaking loose and sliding off and endangering people vehicles other roofs and mechanical and electrical installations below. It also discusses the dangers associated with sliding snow icicles ice dams and ice build up on sidewalks.

Snow and ice sliding off sloped slippery roofs can damage property and injure people as far as 30 feet away from two story facilities. Designing for snow on all such sloping roofs even on inclines as low as 10 calls for a double measure of caution.