Roofs that meet the International Building Code should withstand heavy snow accumulation because of requirements to carry 30 pounds per square foot of pressure, and that should be enough in most cases for sloped roofs. Flat roofs are required to withstand 35 pounds per square foot in Connecticut and have some pitch so that water can drain. Snow on roofs can be measured with online snow-load calculators that can let homeowners know if their roofs need to be cleared.
PB Topical Ref
