PURSUANT TO MONTANA LAW THE MINIMUM DESIGN ROOF SNOW LOAD AFTER ALLOWED REDUCTIONS SHALL BE 30 PSF.
Snow loads shall be determined by the building official. In areas of the state outside of certified city, county and town jurisdictions, the design snow load shall be based on the ground snow loads developed in "Snow Loads for Structural Design in Montana", Civil Engineering Department, Montana State University, 2004 revised edition.
For areas inside a certified city, county or town jurisdiction snow load information shall be obtained from the building official of the certified jurisdiction. Please check the Certified Cities, Counties and Towns list to determine if your location is within that jurisdiction.
For areas outside of certified city, county and town jurisdiction ground snow load information can be obtained in the following ways:
- Use of the "Montana Ground Snow Load Finder" or
- Use the "ASCE 7 Hazard Tool" as an alternate option or
- Contact the State Building Codes for ground snow loads
The Montana Ground Snow Load Finder was developed by Montana State University, Civil Engineering Department in connection with the 2004 revision of "Snow Loads for Structural Design in Montana". To use the Montana Ground Snow Load Finder input the correct latitude and longitude of the location for which you are seeking ground snow load information.
Caution: Latitudes and longitudes must be expressed as decimals. To find the correct latitude and longitude for the location you are seeking ground snow load for you can use one of the various map/topography tools found on-line.
The ASCE 7 Hazard Tool can be used as an alternate method of determining snow and wind loads. Data between the systems may differ slightly as the ASCE 7 uses more data sites and has more years of data configured in.
The Montana Natural Geographic Information System provides several topographic mapping applications. Both Topofinder I and Topofinder II provide tools which can assist in locating the correct latitude and longitude of a specific site.
For areas not listed, not of the same elevation as listed, or locations having some other variable, ground snow loads should be determined by calling the State Building Codes Bureau at 406-841-2056.
