In theory, snow weighs between 6.2 and 12.5 lb/ft³. In practice, this means a 0.3 ft layer of snow can weigh up to 4.1 lb/ft². Wet snow can weigh as much as 31.2 to 37.4 lb/ft³, so the wetter the snow, the heavier the load your roof will be subjected to. Snow that has been there for a while starts to compress under its own weight and will also get heavier. This is why the load-bearing capacity of our patio covers is always expressed in lb/ft² instead of inches of snow.