This is NOT ROOF SNOW load!
This is NOT ROOF LIVE LOAD!

This load is extremely geographical in nature. Contact local building code officials about the necessary ground snow in the area.
Building codes have maps or tables specifying the Ground Snow Load for most areas. In areas of extreme variation of snowfall, the local code official shall specify the Ground Snow Load. The code specified snow load is NOT the roof snow loads. The Ground Snow is reduced by the snow exposure to determine the roof snow load.

The local code official is the final authority on design loads. Many officials have adopted a roof snow load that is different from what would be required by the building code.
An example is the roof snow load is specified as 30 psf but the maps in the building code only require a 20 psf Ground Snow (which would normally be a 14 psf roof snow using the default value for Snow Exposure).
To meet a local requirement of a specified roof snow, the enginnereing departments requires that a ground snow be entered that is HIGHER than the specified roof snow.

This is NOT GROUND SNOW load!
This is NOT ROOF LIVE LOAD!

This load is extremely geographical in nature. Contact local building code officials about the necessary Roof Load in the area.
Building codes have maps or tables specifying the ground snow load for most areas. In areas of extreme variation of snowfall, the local code official shall specify the Ground Snow load. The code specified snow load is NOT the Roof Snow Loads. The Ground Snow is reduced by the Snow Exposure to determine the Roof Snow load. However, occasionally the design load is expressed as a PSF Roof Load. For this reason,
some of the manufactures allows input for "Minimum Roof Snow Load" so the user can specify a minimum Roof Snow Load to be designed.

The local code official is the final authority on design loads. Many officials have adopted a roof snow load that is different from what would be required by the building code. An example is the roof load is specified as 30 psf but the maps in the building code only require a 20 psf Ground Snow.

Buildings codes determine the Roof Snow load based on the Ground Snow load and the Snow Exposure. The Snow Exposure is a factor that reduces the Ground Snow to the Roof Snow used to design the building.

The Possible Snow Exposures are listed across the Snow Input Page. They are as follows:
Normal, Heavily Forested, Open Terrain - No Shelter, Open Terrain - Little Shelter and Sheltered except for IBC 2000, Kentucky (2002) and North Carolina (2002) building codes when they will be as follows:
Partially Exposed, Fully Exposed and Sheltered will be the available selections for IBC 2000 or ASCE7-98 building codes.
While the Snow Exposure factor can change based on the Building Code, generally the snow exposure factor is one of the following:

Normal 0.7
Heavily Forested 0.9
Open Terrain - No Shelter 0.6
Open Terrain - Little Shelter 0.6
Sheltered 0.9

The majority of buildings will fit into the default "Normal", however this shall be confirmed with the local building code official or design professional specifying the design loads. Generally this will be any building that does not fit into one of the categories listed below.
"Open Terrain - No Shelter" refers to a building located in generally open terrain where the roof is exposed on all sides with no shelter afforded by terrain, higher structures or trees with no mechanical equipment on the roof or other obstructions such as parapets or facades.
"Open Terrain - Little Shelter" refers to a building located in generally open terrain where the roof is exposed on all sides with very little shelter afforded by terrain, higher structures or trees with no mechanical equipment on the roof or other obstructions such as parapets or facades.
"Heavily forested" refers to a building located tight in among trees that do not loose their leaves in winter.
"Sheltered" refers to a building located within a distance from the roof of ten times the height of the obstruction above roof level.
The majority of buildings using IBC 2000, Kentucky 01 and North Carolina 02 building codes will fit into the default "Partially Exposed", however this shall be confirmed with the local building code official or design professional specifying the design loads. Generally this will be any building that does not fit into one of the categories.
"Fully Exposed" refers to a building located in generally open terrain where the roof is exposed on all sides with no shelter afforded by terrain, higher structures or trees with no mechanical equipment on the roof or other obstructions such as parapets or facades.
Refer to the local building code documentation for further information.