1 cubic foot of snow can weigh varying amounts, depending on how wet it is? It could weigh 5 psf (pounds per square foot) or it could weigh over 20 psf! The wetter it is, the heavier it is.
Where possible, have snow removed from roofs when consecutive days of snow are in the forecast. Do this very cautiously (following L&I rules) and taking fall precautions for the safety of those on the roof and so the roof is not damaged. Not comfortable doing this yourself? Hire a professional. The aim is to keep snow on the roof to no more than 6-12 inches.
When large amounts of snow are on roofs, inspect attics if possible to identify any damage to structural roofing elements and any leaking. Especially watch older roofs as they are not designed for maximum snow loads like the newer roofs, today.
Be cautious not to push large amounts of snow from higher roofs on to lower roofs, decks, vehicles, or other equipment as the weight of large amounts of heavy snow, falling, could damage these.
Be aware of "ice damming" - this is where warmer air in the attic melts ice on the roof and runs to the gutters and refreezes near gutters and eaves. This ice build up is then covered with new snow, making it difficult to melt. AND make sure walkways are well lit and free of ice for easy traversing from public sidewalks and driveways to your front door.