Reports of roof collapse in the aftermath of multi-foot snowfall points to oneof the dangers posed by major snowstorms.Take 20- to 30-inch snowfall, which can easily hold 2 to 3 inches of waterequivalent. For each square foot of roof surface, a weight of roughly 10 to 15pounds must be borne by a building`s roof and other structural members.
With surface areas of schools and commercial builds reaching many thousands ofsquare feet, tons of snow burden quickly pile up. Under-engineered roofs cangive way under the load.
Strong winds and drifting can heighten the danger all the more. Wind-driftedsnow can become highly concentrated over irregular roofs with loads locallymuch greater than the average load.
Story by AccuWeather.com Senior Meteorologist Jim Andrews.
