Wet snow can be nearly three times heavier than dry, fluffy snow. According to FEMA, a cubic foot of fresh powder might weigh 3 pounds; that amount of wet, packed snow could be more like 21 pounds.
Some experts suggest that removing snow from the roof is unnecessary because a home designed and built to the standards of the local building codes should be structurally equipped to handle the area's snow load. Yet, many homeowners wish to take every available precautionary step and remove snow off of the roofline before it piles up. Not only will this prevent a significant load on your roof, but it will also minimize risk of ice dams. Generally, early fall and late spring snow storms produce the wettest and heaviest snow that can cause tremendous amounts of damage to a weak roof structure.
Consider these safety tips if you remove the snow from your home's roof. Hire a professional with experience to do the job. The combination of heights plus ice makes this one of the more dangerous house chores. If you choose to do the task yourself, have someone outside assist you and remind you not to take dangerous risks. Use a snow rake for pitched roofs (available at most hardware stores) to remove snow from your roof. Start from the edge, work your way up onto the roof with the rake, and leave an inch or two on the roof to prevent causing any damage to the roofing material.
You can also use these tips to protect other structures on your property, like your garage or shed.