Hey, Salma !
You have to search for a CUBIC foot.. That will show you more less accurate answers, eh...
What I found :
1 inch of snowfall on the roof weighs approximately one pound per square foot.
We’ve already established the water content of snow can range anywhere from 5% to 32%, which would mean 1” of snow ranges from .26 pounds per square foot (“PSF”) to 1.66 PSF. To find the average weight of the snow, add those numbers and divide by 2. We get an average of .96 lbs., which is mighty close to 1 pound. (However, you might note right away that especially wet or heavy snow can easily be closer to 2 pounds PSF—note the conditions outside, and use your common sense).
From that, you’ve got a handy formula you can use to determine approximately how many pounds of snow are on your roof: just multiply the inches of snow that have fallen by the square footage of your roof. That number is approximately the number of pounds of snow on your roof.
So, for example, if there are three inches of snowfall and you have a 1000 square foot roof, you’ve got 3,000 pounds of snow up there. Already, that’s like melting down a 2012 Toyota Prius (weighing in at 3042 pounds) into a slab of steel, and putting that slab on your roof.
Note: If you feel the snow on your roof is extremely wet and heavy, you could then multiply this total by 1.66 (for an absolute worst case scenario) – which in this case would equal 4,980 pounds.