The Weight of Snow on a Roof calculator estimates the weight of snow on a roof based on the roofs dimensions and the type and depth of snow.
INSTRUCTIONS: Choose units and enter the following:
- (L) Ridge Length
- (S) Span of Roof
- (P) Pitch of Roof
- (D) Depth of Snow on Roof
- (sT) Type of Snow
Weight of Snow (SW): The Weight of Snow on a Roof is returned in pounds, and the volume of melted water is returned in gallons. However, these can be automatically converted compatible units via the pull-down menu.
The Math / Science
The dimensions of your roof are used to compute the roof's surface area. That area is based on the ridge length, span and the pitch. The depth of the snow combines with the surface area to compute the volume of snow. With that, and the type of snow, one can reasonably estimate the weight of snow on one's roof.
Ignoring minute traces of other substances, snow is frozen water. This equation uses a median value for the Snow Water Equivalent (SWE) based on the type of snow or ice selected:
To reduce the weight of snow on one's roof, many people use a roof rake to pull large quantities of snow off of the roof.
| Type of snow or ice | (kg/m3) |
| Fresh New snow | 50-70 |
| Damp new snow | 100-200 |
| Settled snow | 200-300 |
| Depth hoar | 100-300 |
| Wind packed snow | 350-400 |
| Firn (granular) | 400-830 |
| Very wet | 700-800 |
| Glacier ice | 830-917 |
| Rain/Melt | 997 |
Water, Rain and Snow Calculators:
- Snow Pack to Liquid Water Calculator - Computes the amount of liquid water in snow pack over a geographic area.
- Compute the volume of water in snow or rain
- Compute the Weight/Mass of Snow on an Area.
- Compute the Weight of Snow on a Rectangular Area.
- Compute the Weight of Snow on a Roof.
- Compute the Weight of Snow on a Polygon Shaped Area.
- Compute the Volume of Water in a Rainfall
- Compute the flow rate of a broad crested weir.
- Compute water capillary rise.
- Compute the volume of flood water.
- Compute the number of sandbags needed to build a wall or dike.
- Water Saturation Ratio
- Rain Fall Harvesting Calculator