How the calculation works
Snow load is depth times density. A foot of fresh powder may weigh around 7 pounds per square foot, while a foot of wet, settled snow can weigh 30 or more. A layer of ice weighs far more per inch than any snow. The calculator adds two layers, multiplies by the roof's horizontal area and compares the result with a design load you enter.
Design loads
Buildings are designed for a roof snow load set by local building codes and the engineer's calculations, which vary across Alaska and with roof shape, exposure and drifting. The default here is illustrative only. Your local building department or an engineer can tell you the right figure.
Using it for a claim
If a roof, carport or outbuilding was damaged by snow, record the depth and type of snow with photos and a ruler before removal. That record helps show the weight involved. This calculator is not a structural assessment.
Questions about this tool
Is roof shape accounted for?
No. Drifts, valleys and sliding snow concentrate load in places. This is a simple average.
Is snow load damage covered?
Many homeowner policies cover weight of ice, snow or sleet, sometimes with limits for certain structures. Read your policy.