What is a drift of snow?
Definition: Drifting snow: An ensemble of snow particles raised by the wind to small heights above the ground. The motion of the snow particles is more or less parallel to the ground. Drifting snow may obscure very low obstacles.
What is the snow load for a roof?
Snow load is the downward force on a building’s roof by the weight of accumulated snow and ice. The roof or the entire structure can fail if the snow load exceeds the weight the building was designed to shoulder. Or if the building was poorly designed or constructed.
How much does snow weigh per cubic foot?
“The weight of snow varies greatly. Light fluffy snow may only weigh about seven pounds per cubic foot. More average snow may weigh 15 pounds per cubic foot and drifted compacted snow may weigh 20 pounds or more…”
What pitch roof is best for snow?
Roof pitches of 3:12, 4:12, 5:12, or 6:12 work best for metal buildings in snow country. Anything over a 6:12 pitch tends to make massive amounts of snow slide off the roof without warning. Anything less than 1:12 pitch is a huge mistake in snow-prone climates.
What does a snowdrift look like?
Snowdrifts resemble sand dunes and are formed in a similar manner, namely, by wind moving light snow and depositing it when the wind has virtually stopped, usually against a stationary object. Snow normally crests and slopes off toward the surface on the windward side of a large object.
Can too much snow damage roof?
The weight of snow and ice As weightless as snowflakes seem, combined into a layer of snow, they are heavy and can cause your roof to fail. The damage ranges from leaks to broken shingles and even roof collapse.
What does 2 feet of snow weigh?
Total accumulated weight: Two feet of old snow and two feet of new snow could weigh as much as 60 lbs. per square foot of roof space, which is beyond the typical snow load capacity of most roofs. Ice: One inch of ice equals one foot of fresh snow.
How much does 2 feet of wet snow weigh?
As a rule of thumb, snow weighs approximately 20 pounds per cubic foot, or 1.25 pounds per inch of depth. Depending on moisture content, snow can weigh from 1 pound per cubic foot to over 21 pounds per cubic foot.
How many awards are there in snow drift?
Take control of Yeti and knock out monsters with your ice slide! There are 1 awards in Snow Drift. View All Awards
How to calculate the snow drift surcharge load?
Last, calculate the snow drift surcharge load: To find the maximum surcharge load, multiply the drift height by the snow density: p d = h d γ
What are Leeward snow drifts?
Leeward snow drifts occur when wind blows snow off of a higher elevation roof down onto an adjacent lower roof. See Figure 7-7 from ASCE 7-10 below for a succinct depiction:
Where does the drifting of snow come from?
For a leeward drift (wind from left to right ) , the sliding snow and the drifted snow come from the same source area- the upper level roof. For a step , ASCE 7 is clear in that the larger of the windward and leeward applies – provisions based on observation.