A Snow Guard is a device used to retain snow and ice from falling from one surface to a lower one; in contemporary usage they are installed to prevent snow/ice pack from avalanching and damaging people, plants, and property below. They are most commonly installed in multiples or rows on a structure's roof surface, as a form of avalanche control. Snow Guards are installed with a specific quantity and pattern based on the shape, size and pitch of the roof to provide the most uniform system of retention possible.
Click here to see an example of snow avalanching on a residential building.
Variants of snow guards have been used for over 300 years all round the world where seasonal snowfall is common. In the Alps and Scandinavia, stones and logs are placed on top of roofs to increase friction and retention so that the snow could be used as insulation. Other larger natural or man-made objects and structures have also been used as snow guards (or snow fence) on steep sloping hills to lessen the effects of avalanches in valley regions.
Modern snow guards are made of polycarbonate and/or metals, depending on the type, size, and specific function of the guard. Although primarily installed for functional purposes, panel guards and snow railing are sometimes used to highlight a roof's aesthetic appeal and design. Some manufacturers have designed metal powder-coated color armor shields to match the colors of varying roof types, and snow rails are commonly colored to complement the roofs they protect.
Snow guards are not the same as heat tape or trace heating systems used to melt snow faster; but these products can be and are commonly used together to offer better protection from sliding snow problems. Architects, contractors, and roofers are becoming increasingly aware of the importance and benefits of snow guards in the design process, minimizing the liability of falling snow for homeowners, businesses, and building owners.
In 1976 Jack McMullen of IceBlox Inc. D.B.A. SnoBlox/SnoJax invented the very first clear, polycarbonate snow guard. Then in 1979 a U.S. patent for the first clear plastic injection molded “corrosion proof snow guard” was granted.