Increased outdoor temperature and heat generated by the building can melt snow and ice accumulated on a roof. This melting of the snow results in the formation of a film of water between the snow, the ice and the surface of the roof. Since water acts as a lubricant, snow and ice may fall rapidly and suddenly. The snow stops block the fall and hold the snow and ice on the roof. They allow the snow to fall little by little or even to melt completely on the roof. In addition, snow stops also allow the weight of snow and ice to be spread over the roof, reducing the risk of damage.