Every year snow loading takes a toll on businesses, homes, and public facilities in northern regions. When a record storm occurs, or when a unique combination of moderate snowfall and thawing repeats, structures can be challenged to their design limits. When collapses occur, they are sudden and often catastrophic.

With these repeated stresses and strains, “building to code” is often not a reliable defense against damage or collapse from snow loading. Roof additions, changes to roof mounted equipment, and sustainability upgrades (i.e. “green roofs”) create added opportunities for snow accumulation and drifting that did not exist prior.

Heavy, repeated snowfall and subsequent melting between storms creates a freeze–thaw cycle that can cause roof overloading. Sloped roofs are subject to ice dams and water penetration to interiors; and once such a flow begins, it only ends when the snow is melted off the roof.

For organizations concerned about snow loading prevention and mitigation, it is important to understand where problem areas may lie in their facilities and the actions to be taken in advance of and during the winter weather season. Marsh Risk Consulting’s Property Risk Consulting (PRC) team provides insight into this issue below.