Near record amounts of snow this winter have raised concerns about roof collapses. Snow and ice accumulations on roofs cause a loading which can cause roof collapse when the roof is not strong enough to resist the load. The deeper the snow, the higher the loading.
Brian Holmes and David Kammel, University of Wisconsin-Madison/Extension professors and specialists note that the more dense the snow and ice, the greater the load for a given depth. Rain held in snow can add about 5 pounds per square foot per for each inch of rain.