Snow is stored by mass, not by depth
The mistake that makes snow storage look impossible is treating the pile as the snowfall. Eighty four inches of seasonal snowfall over a 20,400 square foot plowed surface is 142,800 cubic feet of snow as it lay, which is 5,289 cubic yards, which is absurd. But that snow is not all there at once and it is not the same material once it has been pushed.
Take it in the right order. Settled snow at 15 pounds per cubic foot means those 142,800 cubic feet weigh 2,142,000 pounds, or 1,071 tons, across the whole winter. Say thirty percent of it is still on the pile at the peak — the rest melted, sublimated or settled between storms — and you are storing 642,600 pounds. A plowed and refrozen pile runs closer to 28 pounds per cubic foot, so that mass takes 22,950 cubic feet, or 850 cubic yards. The volume fell by a factor of six between the snowfall figure and the pile figure, and every step of that was mass staying constant while density changed.
The carry fraction is the input doing the most work, and it is a genuine unknown rather than a constant. A winter of cold with no thaws stacks nearly everything; a winter that runs above freezing between storms may carry half as much. There is no default worth trusting, which is why it is a field.
Footprint falls as the pile gets taller, and it falls fast
For a cone of fixed side slope, the volume is a third of the base area times the height. Rearranged, the base area is three times the volume divided by the height, which means the footprint is inversely proportional to how high you can stack — independent of the slope entirely.
| Pile height | Footprint for 850 cu yd | Share of a 24,000 sq ft lot |
|---|---|---|
| 4 ft | 17,213 sq ft | 71.7% |
| 8 ft | 8,606 sq ft | 35.9% |
| 12 ft | 5,738 sq ft | 23.9% |
| 16 ft | 4,303 sq ft | 17.9% |
This is why the machine matters more than the lot. A pickup with a blade stacks to maybe five or six feet by ramming the pile. A loader with a bucket stacks to twelve or more, and on the same volume that is a difference of thousands of square feet of parking. The cost of bringing a loader in after a big event is usually argued as a plowing cost, and it is at least as much a real estate cost.
Sight lines end the argument before capacity does
The height field has an upper bound that has nothing to do with the machine. A pile at the corner of a drive aisle blocks the view of a car coming across it, and a pile at the entrance blocks the view of the road. That constraint bites well before the lot runs out of space, and it is the reason snow gets moved to the back of a site or hauled off entirely once it passes a certain volume.
Hauling is the option nobody budgets for. It turns a storage problem into a trucking problem measured in loose cubic yards per truck, and the receiving site is a separate question with its own permissions. The volume figure above is what to quote from; whether a melting site, a designated dump or nothing at all is available where you are is a question for the authority that reviews site drainage.
Every pound of it is water waiting
The mass figure is also a meltwater figure: 642,600 pounds of snow is 77,024 gallons of water, and it does not leave gradually and evenly. It comes off the pile fastest during a warm spell, often with rain falling on top of it, and it runs from wherever the pile is to wherever the grade takes it. A pile placed uphill of the entrance you spent the winter clearing is a sheet of ice every night for a week.
What that water does on its way out is worked through on the snowmelt runoff calculator, and where it ends up if it is going into the ground is the dry well sizing calculator. The plowing that produces the pile in the first place is on the plow route calculator, and the residential version of the same storage problem — where the snow from one driveway goes — is covered at the end of the snow removal time calculator.
Questions people ask
How much space do I need for snow storage on a parking lot?
On the default scenario — 24,000 square feet of lot, 85 percent plowed, 84 inches of seasonal snowfall and 30 percent of it held at the peak — the piles cover about 9,048 square feet at eight feet high, which is 37.7 percent of the lot. Change the pile height to twelve feet and it drops to under 24 percent. The two inputs that move it most are the height you can stack to and the fraction still there at the peak.
Does a snow pile shrink when you plow it into one?
The volume does and the mass does not. Snow that fell at 15 pounds per cubic foot ends up in a pile at something closer to 28 after it has been pushed, rammed and refrozen, so the same weight of snow occupies a bit under half the space. This is the single reason snow storage is possible at all, and it is why estimating pile size from snowfall depth gives an answer several times too large.
How high can you stack plowed snow?
Whatever the machine reaches and the sight lines allow, and the second usually binds first. A truck plow rams a pile to five or six feet. A loader stacks twelve or more. Since footprint is three times the volume divided by the height, going from six to twelve feet halves the ground the piles cover, which on a tight lot is worth more than the machine costs.
Where should snow piles go on a site?
This page will not pick a spot, because the constraints are physical and local rather than arithmetic. What is worth checking before the first storm: the pile must not drain across a surface that has to stay clear, it must not sit over a septic field, a leach line, a utility vault or a meter, it must not block a fire lane or a hydrant, and it must not obstruct sight lines at an aisle or an entrance. Where the meltwater is allowed to discharge is a question for your local authority.
How much water is in a snow pile?
Divide the mass by 8.34 pounds per gallon. The default pile holds 642,600 pounds of snow, which is 77,024 gallons of water. It does not come out evenly: most of it leaves during a thaw, frequently with rain falling on the pile at the same time, and the pile is often the last thing on a site still shedding water days after everything else has dried.