Boat Hill, where I live since two years back, is a 70s tract-housing estate where roofs are almost flat. Snow thus tends to build up on them. Of course, pile enough snow onto any structure and it will collapse. But I’ve come across a curious notion here. Several neighbours have told me to beware wet snow “because it’s so heavy”.
They’re not talking about snow that becomes secondarily soaked by rain that adds to its weight. They believe that if I have a tonne of powdery snow at -10 Celsius on my roof, I’m OK, but if that tonne approaches 0 Celsius and compacts down into a thinner, less fluffy layer, it will break my roof.
As far as I understand, they’re confusing weight and density. A shovel of powdery snow is lighter than a shovel of slush. But when you shovel slush, you need to shift fewer shovels of the stuff to get your yard (or roof) free of snow.