Snow Load by Zip Code
Find your local ground snow load before you frame the roof
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What Ground Snow Load Means for Your Concrete Project
Ground snow load (pg) is the design weight of accumulated snow on flat, unobstructed ground at your site, in pounds per square foot (psf). It is the single number that drives roof framing sizing, deck snow design, and every prescriptive IRC table that mentions snow loading. Get it wrong on the low side and you risk a roof collapse under a heavy winter. Get it wrong on the high side and you will spend thousands on rafters, trusses, and connectors you did not need.
The IRC sets ground snow loads in Section R301.2(5), which in the 2018 and 2021 IRC appears as "Figure R301.2(5) Ground Snow Loads, Pg, for the United States." The 2024 IRC replaces the small printed map with a footnote directing designers to the ASCE 7-22 Ground Snow Load Geodatabase, accessible through the free ASCE Hazard Tool for any site-specific value.
Pg flows into a chain of design decisions: roof rafters, truss bracing, deck joist sizing under IRC R507, snowdrift loads on lower roofs, and the gravity loads carried down to your footings and into the soil. A house in Bangor, Maine designed for a 20 psf snow load is a future insurance claim. A house in Tucson designed for 50 psf is a waste of lumber.
Key Rule: Ground Snow Load (pg) Is Not Roof Snow Load (pf)
This trips up almost every DIYer and a surprising number of contractors. Ground snow load is the unmodified mapped value. Flat-roof design snow load is calculated from it:
pf = 0.7 × Ce × Ct × Is × pg (ASCE 7-22 Equation 7.3-1)
Where Ce is the exposure factor (1.0 for most partially-exposed suburban sites), Ct is the thermal factor (1.0 for a heated building), and Is is the importance factor (1.0 for a normal house). For a heated home with normal exposure and pg = 40 psf, the flat-roof design load is pf ≈ 28 psf, not 40. Sloped roofs are reduced further by the slope factor Cs. Use the right value in the right context: your trusses get designed for pf, your inspector cites pg.
Once you have your pg, head to our concrete footing calculator to size the footings carrying the load down to soil.
Ground Snow Load by State: Complete Table
The values below are representative ASCE 7-22 Risk Category II strength-level ground snow loads, plus the typical range across each state. Areas marked CS are Case Study regions, where local elevation and microclimate vary so dramatically that ASCE 7-22 declines to map them and a site-specific engineering analysis is required.
| State | Typical pg Range (psf) | Capital / Major City pg | Notes |
|---|---|---|---|
| Alabama | 0 – 10 | Montgomery: 0; Birmingham: 5 | Higher elevations CS |
| Alaska | 25 – 300 | Anchorage: ~50; Juneau: ~60 | Per IBC Table 1608.2; local officials set values |
| Arizona | 0 – 15 | Phoenix: 0; Flagstaff: 50–80 (CS) | Mountain zones CS |
| Arkansas | 5 – 15 | Little Rock: 10 | IRC base |
| California | 0 in coastal/valley | Sacramento: 0; LA: 0; Truckee: CS | Sierra is CS |
| Colorado | 20 – 100+ | Denver: 43 pg(asd); Boulder: 25–30 | Most foothills/mountains CS |
| Connecticut | 30 – 50 | Hartford: 30–35 | — |
| Delaware | 15 – 25 | Dover: 20 | — |
| Florida | 0 | Tallahassee: 0; Miami: 0 | — |
| Georgia | 0 – 10 | Atlanta: 5 | — |
| Hawaii | 0 | Honolulu: 0 | Mountains by AHJ |
| Idaho | 20 – 120+ | Boise: 25; Sun Valley: CS | U. of Idaho 2015 study |
| Illinois | 20 – 35 | Springfield: 20; Chicago: 25 | — |
| Indiana | 20 – 30 | Indianapolis: 20 | — |
| Iowa | 25 – 40 | Des Moines: 30 | — |
| Kansas | 15 – 25 | Topeka: 20 | — |
| Kentucky | 10 – 20 | Frankfort: 15 | — |
| Louisiana | 0 – 5 | Baton Rouge: 0 | — |
| Maine | 50 – 100+ | Augusta: 70; Bangor: 80 | — |
| Maryland | 25 – 60 | Annapolis: 30; Baltimore: 60 | 7-22 raised Baltimore from 25 to 60 psf |
| Massachusetts | 30 – 70 | Boston: 40; Worcester: 50 | 780 CMR Table R301.2.5 by jurisdiction |
| Michigan | 25 – 70 | Lansing: 30; Marquette: 80 | State zone map |
| Minnesota | 50 or 60 (state-mandated) | St. Paul: 50; Duluth: 60 | MN Rule 1303.1700 |
| Mississippi | 0 – 5 | Jackson: 0 | — |
| Missouri | 15 – 25 | Jefferson City: 20; St. Louis: 20 | — |
| Montana | 30 – 100+ | Helena: 30; Bozeman: CS | State min roof load 30 psf |
| Nebraska | 20 – 35 | Lincoln: 25; Omaha: 25 | — |
| Nevada | 0 – 50+ | Carson City: 30; Las Vegas: 0 | Sierra CS |
| New Hampshire | 50 – 100 | Concord: 70; Manchester: 60 | CRREL TR-02-6 governs |
| New Jersey | 20 – 35 | Trenton: 25; Newark: 25 | — |
| New Mexico | 10 – 40 | Santa Fe: 25; Albuquerque: 10 | Mountain CS |
| New York | 20 – 60+ | NYC: 25 (NYC BC §1608.2); Albany: 40; Buffalo: CS | ~half of state CS; 2025 BCNYS references ASCE 7-22 |
| North Carolina | 10 – 30 | Raleigh: 15; Asheville: 20–30 | Appalachian CS |
| North Dakota | 35 – 50 | Bismarck: 40; Fargo: 45 | — |
| Ohio | 15 – 25 | Columbus: 20; Cleveland: 25 | — |
| Oklahoma | 5 – 20 | Oklahoma City: 10 | — |
| Oregon | 20 – 100+ | Salem: 20; Portland: 25; Bend: 40 | State min roof load 20 psf × I |
| Pennsylvania | 20 – 50 | Harrisburg: 25–30; Pittsburgh: 25 | NE/mountains CS |
| Rhode Island | 25 – 35 | Providence: 30 | — |
| South Carolina | 0 – 10 | Columbia: 5; Charleston: 0 | — |
| South Dakota | 30 – 45 | Pierre: 35; Sioux Falls: 35 | — |
| Tennessee | 10 – 20 | Nashville: 10; Knoxville: 15 | Smokies CS |
| Texas | 0 – 10 | Austin: 0; Houston: 0; Amarillo: 10 | — |
| Utah | 30 – 150+ | Salt Lake City: 30; Park City: 75+ | Utah Code 15A-3-202; mostly CS |
| Vermont | 40 – 80 | Montpelier: 60; Burlington: 50 | State min roof load 40 psf |
| Virginia | 15 – 35 | Richmond: 25; Roanoke: 20 | Blue Ridge CS |
| Washington | 15 – 100+ | Olympia: 25; Seattle: 20; Spokane: 40 | Cascades CS; SEAW analysis |
| Washington, D.C. | 25 to 62 | DC: 62 | ASCE 7-22 raised DC from 25 to 62 psf |
| West Virginia | 15 – 40 | Charleston: 20; Morgantown: 25 | Allegheny CS |
| Wisconsin | 30 – 50 | Madison: 30; Milwaukee: 30 | SPS 321 Uniform Dwelling Code |
| Wyoming | 30 – 100+ | Cheyenne: 30; Jackson: 80+ | Mountain CS |
Sources: ASCE 7-22 Hazard Tool, IRC Figure R301.2(5), state building code amendments, USDA Forest Service Snow Load Information, and CRREL/extension studies. These are reference values; for permit submittal, run your exact site coordinates through the ASCE Hazard Tool.
State Capital Required Snow Loads at a Glance
A compact lookup for permit-discussion design values at each state capital. These are summary numbers only. Always confirm the operative value at your site with the AHJ and the ASCE Hazard Tool before permit drawings.
| Capital | State | Design pg (psf) |
|---|---|---|
| Montgomery | AL | 0 |
| Juneau | AK | 60 |
| Phoenix | AZ | 0 |
| Little Rock | AR | 10 |
| Sacramento | CA | 0 |
| Denver | CO | 43 (asd) |
| Hartford | CT | 30 |
| Dover | DE | 20 |
| Tallahassee | FL | 0 |
| Atlanta | GA | 5 |
| Honolulu | HI | 0 |
| Boise | ID | 25 |
| Springfield | IL | 20 |
| Indianapolis | IN | 20 |
| Des Moines | IA | 30 |
| Topeka | KS | 20 |
| Frankfort | KY | 15 |
| Baton Rouge | LA | 0 |
| Augusta | ME | 70 |
| Annapolis | MD | 30 |
| Boston | MA | 40 |
| Lansing | MI | 30 |
| St. Paul | MN | 50 |
| Jackson | MS | 0 |
| Jefferson City | MO | 20 |
| Helena | MT | 30 (min roof) |
| Lincoln | NE | 25 |
| Carson City | NV | 30 |
| Concord | NH | 70 |
| Trenton | NJ | 25 |
| Santa Fe | NM | 25 |
| Albany | NY | 40 |
| Raleigh | NC | 15 |
| Bismarck | ND | 40 |
| Columbus | OH | 20 |
| Oklahoma City | OK | 10 |
| Salem | OR | 20 (min) |
| Harrisburg | PA | 25 |
| Providence | RI | 30 |
| Columbia | SC | 5 |
| Pierre | SD | 35 |
| Nashville | TN | 10 |
| Austin | TX | 0 |
| Salt Lake City | UT | 30 |
| Montpelier | VT | 60 |
| Richmond | VA | 25 |
| Olympia | WA | 25 |
| Charleston | WV | 20 |
| Madison | WI | 30 |
| Cheyenne | WY | 30 |
| Washington | DC | 62 |
These are summary values for design discussion. Always run the actual site coordinates through the ASCE Hazard Tool for permit-grade numbers and confirm with your local AHJ.
Why a State Average Is a Bad Permit Number
State-level snow loads are great for "is my project in a 20 psf zone or a 70 psf zone?" planning. They are dangerous on permit drawings. Within one state, pg can swing by a factor of five or more.
Colorado is the textbook example. Eastern plains see 20–30 psf. Front Range cities like Denver use a 43 psf allowable-stress-design pg. Mountain communities at 8,000+ feet are Case Study regions where engineers must perform site-specific analyses using Colorado Design Snow Loads 2016 by the Structural Engineers Association of Colorado. Building to "Colorado average" would over-build Denver and under-build Aspen.
New York is similarly split. NYC is fixed at 25 psf by NYC Building Code §1608.2, regardless of the ASCE map. Albany jumps to 40 psf. Buffalo, the Tug Hill Plateau, and the Adirondacks fall into Case Study territory with localized values that can exceed 100 psf in lake-effect bands. As of January 1, 2026, the Building Code of New York State references ASCE 7-22 reliability-targeted values directly.
Maine and New Hampshire show how cold inland climates drive loads higher than coastal areas. Portland, Maine sits around 50 psf; interior Aroostook County exceeds 100 psf. New Hampshire's official source is the U.S. Army Corps of Engineers ERDC/CRREL TR-02-6, which the state code explicitly incorporates.
Maryland and DC got hit hardest by the ASCE 7-22 update. Baltimore's ground snow load jumped from 25 psf in ASCE 7-16 to 60 psf in ASCE 7-22, per Maguire et al. in Structure Magazine (February 2022): in ASCE 7-16, pg is 25 psf (× 1.6 load factor); the reliability-targeted ASCE 7-22 value of pg for Risk Category II is 60 psf (× 1.0 load factor) at this location. Washington, DC moved from 25 to 62 psf in the same revision.
The Bottom Line
For any permitted structure, run your site's exact coordinates through the ASCE 7 Hazard Tool for an ASCE 7-22 value, then confirm with your local building department. State averages are a starting point, not a permit drawing.
How Snow Load Affects Concrete and Foundation Design
Snow load is mainly a roof and framing problem, but it flows through to the concrete.
Bigger footings. A roof carrying 50 psf snow drives a much higher gravity load to bearing walls and footings than a 10 psf roof. IRC Table R403.1(1) footing widths scale with the total wall load, which scales with snow load. Going from 30 psf to 70 psf can push a one-story footing from 12 inches wide to 16 inches. See the concrete footing size chart for the prescriptive tables.
Deck design. IRC R507 requires decks to be designed for the greater of 40 psf live load or the local ground snow load. In a 70 psf snow zone, you cannot design a deck for 40 psf — joist spans, post sizes, and footing depths all increase. Use the post hole calculator once you have your post size dialed in, and cross-check pier depth against the deck footing size chart.
Garage and shed slabs. Heavy roof snow combined with freeze-thaw cycling can crack unreinforced slabs. In 50+ psf zones, consider rebar mats and thicker edge beams. IRC R301.2.1.1 caps prescriptive light-frame construction at pg = 70 psf — above that, the whole structure must be engineered. For sizing strip footings on snow-loaded walls, run the numbers in our footing calculator; for project-cost context, see the concrete slab cost guide.
States with Amended Snow Load Requirements
Several states publish their own ground snow load tables or rules that supersede IRC Figure R301.2(5). If you are building in one of these states, skip the ASCE map and go directly to the state document.
- Massachusetts: 780 CMR 9th/10th Ed. Table R301.2.5 (jurisdiction-by-jurisdiction).
- Michigan: Figure 1608.2 zone map.
- Minnesota: Rule 1303.1700 — 60 psf in 29 named northern counties, 50 psf in all others.
- New Hampshire: ERDC/CRREL TR-02-6 case studies for all cities and towns.
- Vermont: Annex VII to the 2012 Fire & Building Safety Code; 40 psf minimum roof load statewide.
- Montana: ARM 24.301.146; 30 psf minimum roof load.
- Oregon: Specialty Code; 20 psf × I minimum roof load.
- Washington: SEAW Snow Load Analysis for Washington (1995, updated).
- Idaho: University of Idaho 2015 Ground Snow Loads.
- Wisconsin: SPS 321 Uniform Dwelling Code (Wisconsin does not adopt the IRC for residential).
- New York: 2025 BCNYS references ASCE 7-22 directly, effective January 1, 2026.
- Utah: Utah Code 15A-3-202 state-specific tables.
How to Find YOUR Exact Snow Load
The tables above are a strong starting point. For permit approval, you need the official number for your specific site. Four steps in order of reliability.
Step 1: Check the State Table Above
Use it to set expectations and budget. If you are clearly in a high-load region, get an engineer involved early.
Step 2: Use the ASCE 7 Hazard Tool
Go to asce7hazardtool.online, enter your address or lat/long, select ASCE/SEI 7-22 and Risk Category II for a single-family home, and the tool returns your pg in both strength-level and allowable-stress-design (ASD) forms, plus the 20-year MRI value and winter wind parameter W2. Save the PDF for your permit packet.
Step 3: Call Your Local Building Department
Many jurisdictions publish a single official pg on their permit checklist. NYC mandates 25 psf regardless of the ASCE map. Denver mandates 43 psf pg(asd). Always confirm in writing.
Step 4: Check State Amendments
Use the list in the section above to confirm you are not in one of the dozen states with overriding state-level snow load tables. If you are, the state document is the operative source — not the ASCE map.
Once you have your pg, drop it into IRC Equation pf = 0.7 × Ce × Ct × Is × pg to get your roof design load, then check IRC R507 for deck requirements. Your engineer or truss supplier will run the snow-drift, unbalanced-load, and rain-on-snow analyses required by ASCE 7-22 Chapter 7.
Plan Your Snow Load Right the First Time
Ground snow load is the input that decides whether your roof carries six feet of February snow or collapses under it. Whether you are in Concord, NH at 70 psf or Phoenix at zero, knowing your local pg before you lock in framing is the difference between a 30-year structure and a winter insurance claim.
Use the tables above as your starting reference, confirm with the ASCE Hazard Tool and your local building department, and then let our calculators handle the math on the concrete that will carry the load.
Frequently Asked Questions
Is ground snow load the same as roof snow load?
No. Ground snow load (pg) is the design weight of snow on flat ground. Flat-roof design snow load is pf = 0.7 × Ce × Ct × Is × pg. For a typical heated single-family house with normal exposure, the flat-roof load is about 70% of pg; sloped roofs are reduced further by the slope factor Cs.
Where does IRC R301.2(5) come from?
It is a reproduction of the ASCE 7 ground snow load map. The 2018 and 2021 IRC publish ASCE 7-16 data. The 2024 IRC adopts ASCE 7-22 reliability-targeted values and directs designers to the ASCE Hazard Tool Geodatabase for site-specific lookups.
What changed in ASCE 7-22 snow loads?
ASCE 7-22 replaced the 50-year MRI approach with reliability-targeted strength loads at a load factor of 1.0. Most structures shifted by ±5–15%. Some cities saw large jumps — Baltimore went from 25 to 60 psf. Case Study regions were reduced by more than 90% because state-specific studies are now built in.
My building department gave me a number lower than the ASCE map. Which do I use?
The number in your permit packet from the AHJ is what your inspector will check against. For permit drawings, the AHJ value is operative. Get the value in writing and keep it in your project file.
What is a "Case Study" zone?
A region where local topography and elevation cause snow loads to vary so dramatically that no single mapped value is appropriate. ASCE 7-22 requires a licensed engineer to perform a site-specific analysis using nearby weather station data.
Does IRC limit prescriptive design using snow load?
Yes. IRC R301.2.1.1 caps prescriptive light-frame, cold-formed-steel, masonry, and SIP construction at pg ≤ 70 psf. Above that, the building must be designed in accordance with accepted engineering practice.
Do I need to add a rain-on-snow surcharge?
ASCE 7-22 §7.10 raised the rain-on-snow surcharge to 8 psf, up from 5 psf in ASCE 7-16. Apply it where pg ≤ 20 psf on low-slope roofs.
Does my deck have to be designed for snow load?
Yes, per IRC R507.1: decks must be designed for the greater of 40 psf live load or the local ground snow load. In Boston (40 psf) the values are equal; in Concord, NH (70 psf) snow load governs.