A roof snow load calculator helps Canadian homeowners, contractors, and property managers determine how much weight accumulated snow is placing on a roof structure. Canada's National Building Code specifies snow load design requirements for different climate zones, and understanding actual snow load versus your roof's design capacity is important for structural safety during heavy winter storms. Snow density varies significantly: fresh light fluffy snow weighs approximately 50 kg per cubic metre, packed snow around 200 kg/m³, wet heavy snow up to 400 kg/m³, and ice approximately 900 kg/m³. A 30 cm accumulation of wet heavy snow on a 10m x 8m roof adds over 9,600 kg of weight. When to Remove Snow From Your Roof: Ontario and Canadian building professionals recommend removing snow when loads approach 200 kg/m² or when you notice signs of structural stress such as cracking sounds, sticking doors, or visible roof deflection. Always use a roof rake from the ground rather than climbing onto a snow-covered roof.