Building Planning Tool
Snow Load Reference
Estimate typical ground snow loads for your area and learn how local climate conditions can influence steel building design.
This tool is intended for planning and educational purposes only. Final design snow loads must always be verified by your building manufacturer, engineer of record, and local building department.
Find your snow load
Search by ZIP code, city, county, or state.
Snow Load by State
Click any state to see typical snow conditions, regional considerations, and how those loads influence steel building design. Colors reflect the typical lowland category — mountain and high-elevation zones are frequently much higher.
- Very Low0–5 PSF
- Low5–15 PSF
- Moderate15–30 PSF
- High30–50 PSF
- Very High50+ PSF
Southeast
Northeast
Midwest
Mountain
West
Southwest
Pacific
Non-Contiguous
What does PSF actually mean?
PSF stands for pounds per square foot. A 30 PSF ground snow load means a design snowpack that weighs 30 pounds on every square foot of ground — roughly 30 inches of typical fluffy snow, or 6 inches of dense wet snow.
Ground snow load (Pg) is the weather-derived value published by ASCE 7 for your area. Roof snow load (Pf) is what the roof is actually designed to carry — the ground value adjusted for wind exposure, thermal condition, importance, and slope. Roof snow is usually less than ground snow — but drift, sliding, and unbalanced load conditions can push local roof loads higher.
Engineering matters because snow doesn't sit flat. It drifts against walls, accumulates in valleys, and slides off warm smooth panels onto porches and lean-tos. A sealed engineer packages all of that into a real design.
How snow affects steel buildings
- Roof framingPurlin size, spacing, and rafter/truss depth all scale with design snow load.
- PurlinsHigher loads tighten purlin spacing — sometimes 4' or 3' o.c. instead of 5'.
- ColumnsSnow reactions transfer down to base plates, anchor bolts, and foundations.
- FoundationsPiers, slab thickness, and rebar are sized in part for snow-driven column loads.
- Roof pitchSteeper pitches shed snow and reduce the slope factor Cs on smooth cold roofs.
- DrainageSnowmelt has to leave the roof — gutters, downspouts, and eaves are sized accordingly.
How Snow Load Affects Common Buildings
Garages
Roof framing and column base plates sized for local snow and drift near adjacent structures.
Commercial Buildings
Longer clear spans mean more sensitivity to unbalanced and drift loads, especially near parapets and RTUs.
Warehouses
Wide-span roofs make snow drift against multi-height rooflines a primary design driver in snow country.
Barndominiums
Steeper pitches shed snow better but generate slide loads onto porches, lean-tos, and outbuildings.
Agricultural Buildings
Open, unheated pole and steel structures use a cold-roof thermal factor — often the design load is close to the ground snow load.
Aircraft Hangars
Large clear spans and door pockets require careful drift analysis where the roof steps against tail sections and adjacent structures.
Workshops
Insulation, heating, and roof pitch all interact with snow load — a heated shop reduces the thermal factor.
Horse Barns
Center-aisle barns with attached shed rows create step conditions where drift loads accumulate.
RV Buildings
Tall eaves and wide bays are common — snow slide loads onto adjacent lean-tos need to be checked.
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Common Questions About Snow Loads
Important disclaimer
This Snow Load Reference tool provides approximate planning information only. Actual design snow loads are determined by local building codes, engineering requirements, elevation, exposure, roof configuration, and jurisdictional requirements. Always confirm final design loads with your building manufacturer, engineer of record, and local permitting authority before purchasing or constructing a building. Values shown are not official code requirements.