Snow itself can get pretty heavy, but more risky I think is repeated melting and refreezing. You can wind up with a large mass of ice that can really fuck up a roof or overhang.
Well, I have seen drains clog up so bad that the parapets act like a bowl and capture the ~1m of water with the roof still staying mostly intact (although seepage would have greatly increased there), so something other than my calculations is holding up that roof.
So I guess one would have to rely on the melting-refreezing to break down the roof, considering that without the phenomenon, the ice would be pretty fluffy and light.
Snow itself can get pretty heavy, but more risky I think is repeated melting and refreezing. You can wind up with a large mass of ice that can really fuck up a roof or overhang.
Well, I have seen drains clog up so bad that the parapets act like a bowl and capture the ~1m of water with the roof still staying mostly intact (although seepage would have greatly increased there), so something other than my calculations is holding up that roof.
So I guess one would have to rely on the melting-refreezing to break down the roof, considering that without the phenomenon, the ice would be pretty fluffy and light.