Snow Load
by ZIP Code

Ground snow load is the weight of snow per square foot on flat ground, used in structural engineering design. It is defined by ASCE 7-22 and represents the 50-year return period snow load — meaning there is a 2% chance of this load being exceeded in any given year. It is measured in PSF (pounds per square foot).

PSF stands for pounds per square foot. It is the standard unit for measuring snow load in structural engineering. For example, a ground snow load of 30 PSF means 30 pounds of snow weight is expected per square foot of ground area for design purposes.

ASCE 7-22 is the "Minimum Design Loads and Associated Criteria for Buildings and Other Structures" published by the American Society of Civil Engineers. It is the primary reference standard used by building codes in the United States to determine structural design loads including snow, wind, seismic, and rain loads.

If your area has a ground snow load above 30 PSF, your roof structure needs to be specifically engineered for snow loads. Even in lower snow load areas, flat or low-slope roofs can accumulate drifting snow. If you are building or renovating, always consult a structural engineer and your local building code.

A Case Study zone is an area where ASCE 7-22 does not provide a specific ground snow load value because loads vary significantly due to elevation, terrain, or microclimate effects. In these areas, a site-specific case study by a licensed engineer using local weather station data is required to determine the design snow load.

Yes. Especially in mountainous areas, snow load can vary significantly with elevation within the same ZIP code or county. The values shown are representative of the county-level ASCE 7-22 polygon data. For precise values at a specific site, consult a structural engineer familiar with local conditions.