How much snow....

Smart move to get rid of it Bill, a few years ago we had about 4 feet in a few weeks here in Mass. My mom's house was a single story ranch. There was rain coming, so I climbed up and shoveled it off. Was glad I did, the snow had compressed itself down to about 2 1/2 feet, but not lost any of its weight. I ended up pushing it off the roof rather than shovel, but it was heavy.
 
AKBill said:
We got another foot last night, and expect another foot today. That would put total snow on the roof at 6 feet or so. It's going to warm up and rain this week. That is what made concerned. Who knows it may have been fine, I just did not want to have to call Jake from State Farm about an avalanche in my living room...:rolleyes:

edit: and to beat all the worm drive for the snow blower locked up last night...:(
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im sure a licensed structural engineer will come in here to tell me I’m wrong but…. Are you seeing any changes in your home, like interior doors not closing, slight separation/cracks at wall/ceiling connections, etc. if not, I would not worry about.
 
My house here has a 12/12 pitch and metal roof. The one in CO has 14/12 pitch and metal roof. Snow doesn't hang around long. :D
 
NoBShere said:
im sure a licensed structural engineer will come in here to tell me I’m wrong but…. Are you seeing any changes in your home, like interior doors not closing, slight separation/cracks at wall/ceiling connections, etc. if not, I would not worry about.
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Until it rains. Rain adds terrific weight to snow. Sometime, take a pot of fresh, powdery snow and put it on the stove and heat it and see how much water is there. Almost none. Takes numerous refills of snow to make enough for a couple of cups of coffee. A half-inch of rain is equivalent to a terrific amount of snow. A half-inch of rain on a modest 1500 square foot roof weighs almost 4000 pounds. Snow on the roof will soak it up.
 
how much snow could a snow thrower throw if a snow thrower could throw snow?
 
Dan Thomas said:
Until it rains. Rain adds terrific weight to snow. Sometime, take a pot of fresh, powdery snow and put it on the stove and heat it and see how much water is there. Almost none. Takes numerous refills of snow to make enough for a couple of cups of coffee. A half-inch of rain is equivalent to a terrific amount of snow. A half-inch of rain on a modest 1500 square foot roof weighs almost 4000 pounds. Snow on the roof will soak it up.
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an inch of rain is often the equivalent of a foot snow, that is a rough rule of thumb in my neck of the woods. Also, Rain normally means higher temps which means snow melts which means less snow.

And 4000 pounds across a 1500 sq ft code compliant roof doesn’t sound like that much to me.
 
4000 lbs is too low.

The googles tell me 1" of water is 623 gallons per 1,000 square feet. On 1500 ft, that is 934.5 gallons, at 8 lbs per gallon, 7476 lbs. That is just under 5 lbs per sq ft, which still doesn't sound like anything. At 6' of snow, that's 30 lbs/sq ft.

Maybe it's more significant because every sq ft has weight on it. At 6' of snow, that's about 45,000 lbs of snow on 1500 sq ft.
 
NoBShere said:
im sure a licensed structural engineer will come in here to tell me I’m wrong but…. Are you seeing any changes in your home, like interior doors not closing, slight separation/cracks at wall/ceiling connections, etc. if not, I would not worry about.
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Nope, I agree.
In big winters people would call me and ask if they had too much snow on their roof. My answer was always the same: it is a lot cheaper to hire a contractor to shovel your roof than it is to hire me to analyze it.
 
bflynn said:
4000 lbs is too low.

The googles tell me 1" of water is 623 gallons per 1,000 square feet. On 1500 ft, that is 934.5 gallons, at 8 lbs per gallon, 7476 lbs. That is just under 5 lbs per sq ft, which still doesn't sound like anything. At 6' of snow, that's 30 lbs/sq ft.

Maybe it's more significant because every sq ft has weight on it. At 6' of snow, that's about 45,000 lbs of snow on 1500 sq ft.
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Figure a density of about 15pcf (if it is really cold it could be less). The highest I have ever measured was 23pcf and that was after rain on snow. There have been higher densities measured but that only happens with a very deep and old snow pack. The bottom layers transform to ice over time
 
coach said:
Nope, I agree.
In big winters people would call me and ask if they had too much snow on their roof. My answer was always the same: it is a lot cheaper to hire a contractor to shovel your roof than it is to hire me to analyze it.
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You sound like the kind of engineer I like to work with.
 
bflynn said:
4000 lbs is too low.

The googles tell me 1" of water is 623 gallons per 1,000 square feet. On 1500 ft, that is 934.5 gallons, at 8 lbs per gallon, 7476 lbs. That is just under 5 lbs per sq ft, which still doesn't sound like anything. At 6' of snow, that's 30 lbs/sq ft.

Maybe it's more significant because every sq ft has weight on it. At 6' of snow, that's about 45,000 lbs of snow on 1500 sq ft.
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Your numbers line up with mine. I was talking a half-inch of rain, not an inch.

Snow isn't just snow. The temperatures that snow forms in has a huge impact on its density. Temps not far below freezing make heavy, wet snow. It piles up quickly and breaks stuff. It sticks to tree branches and pulls them down. In much lower temps the flakes are tiny, almost like dust, and the snow is powdery, low-density stuff that doesn't stick to anything, but the wind drives it into massive drifts where the crystals lock together to form something like styrofoam. You can walk on those drifts a long way above the ground. You can saw the stuff into blocks and make snow houses. It won't roll into a ball to make a snowman. It's not sticky.

Go here and scroll a little more than halfway down the page to see the effect temps have on snow: https://roofonline.com/weights-measures/weight-of-snow/
 
No matter how much it snows in this part of Montana it is never a worry . Keeping the shingles on because of wind is more of a problem.
A few years back on the West side of the great divide snow was a big problem to all the large box stores . They hired folks with snow blowers to move it off the flat roofs . One store claimed it ate the totals years profit to keep the snow removed.
Some nice Flathead Lake summer properties learned why their neighbors didn't have big decks out over the lake .
On this side of the divide , After blowing around different directions the snow here becomes about the same consistency as concrete. Drifts get hard enough to drive over. Then come the chinook winds and mud .
The joy of it. :)
 
Southpaw said:
No matter how much it snows in this part of Montana it is never a worry . Keeping the shingles on because of wind is more of a problem.
A few years back on the West side of the great divide snow was a big problem to all the large box stores . They hired folks with snow blowers to move it off the flat roofs . One store claimed it ate the totals years profit to keep the snow removed.
Some nice Flathead Lake summer properties learned why their neighbors didn't have big decks out over the lake .
On this side of the divide , After blowing around different directions the snow here becomes about the same consistency as concrete. Drifts get hard enough to drive over. Then come the chinook winds and mud .
The joy of it. :)
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Yup. Same sort of snow we get here in Saskatchewan. In BC, where I grew up, the temperatures were more moderate and the snow could get heavy real quick.

Chinook weather here right now. Up to -2°C. Was -29°C yesterday. Supposed to reach +5 by Wednesday.
 
Had 8' of snow on my roof this past winter, not as much as some years before. The houses around Vanderhoof BC are built for the winters we get. Never shovel off one side of a roof, then go do the opposite side, it puts a twisting force on the house. Do a bit from one side, then the other, and keep alternating. I have seen a house collapse from that being done, they should have left it alone.
 
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