Solar Wind and Snow Load Criteria by State

A solar project enters design in a new state. The intake sheet lists the city, module count, and roof type. It does not identify the adopted code, load standard, local amendments, or accepted snow source. That missing load basis can invalidate every attachment check that follows.

Direct answer. No safe table can assign one solar wind speed or snow load to an entire state. Start with the enforceable code record, then run the address through the correct hazard source. Check state and local amendments next. Finally, obtain written direction from the Authority Having Jurisdiction and the responsible structural professional.

This solar wind and snow load criteria by state guide covers all 50 states and the District of Columbia. It gives permit teams a source path, not project calculations. Every load value in the matrix remains unresolved until the project facts are known.

Why a state is a routing field, not a design value

State names are useful for triage. They help a permit manager find adoption records, state agencies, and local enforcement rules. They cannot size an attachment or member.

Wind and snow criteria change within many states. Coordinates, elevation, terrain, coastlines, mountain ranges, and special wind regions can alter the hazard. The structure also changes the design demand. Roof height, geometry, exposure, parapets, and array position affect wind pressure. Roof slope, thermal condition, drift geometry, and adjacent height changes affect snow demand.

The governing edition also matters. The American Society of Civil Engineers publishes ASCE 7. Publication does not make a new edition enforceable everywhere. A state or locality must adopt a building code that references an edition. Amendments can then change how the jurisdiction applies it.

Treat each state row below as a route to evidence. Do not copy a climate value from another project. Do not assume the newest standard controls. Do not let a software default become the undocumented basis of design.

Build the load basis from four records

A defensible load basis uses four records. Keep them together in the project folder. The calculation cover sheet should point back to them.

1. Enforceable code-adoption record

Identify the building code and load standard that apply at the site. The International Code Council adoption resources are a useful starting point. The adopting law, ordinance, or agency record remains the controlling evidence.

Some states manage a statewide code. Others let cities and counties adopt their own editions. A few use different systems for state buildings, modular construction, or unincorporated areas. Ask which agency has legal authority over this project type and address.

2. Hazard output for the selected edition and coordinates

Run the exact site through the ASCE Hazard Tool when the adopted standard and hazard permit that path. Save the address, coordinates, selected edition, risk category, output date, and report file.

The output is a hazard input. It is not a completed design. It does not choose exposure, resolve local amendments, calculate array pressures, or check a connection. See the ASCE wind load guide for the calculation path after source selection.

3. State or local amendment, map, bulletin, or study

Search the state code portal and AHJ library. A local ordinance may adopt a different edition or add design criteria. Mountain jurisdictions may publish snow maps, tables, or case-study procedures. Coastal areas may add wind-borne debris, product approval, or special inspection rules.

Record the document title, revision date, page, and link. A screenshot without source context is weak evidence. A map image without coordinates or legend is also weak evidence.

4. Written AHJ and responsible-professional confirmation

Close unresolved questions before calculations begin. Ask the Authority Having Jurisdiction which edition, map, local amendment, and submittal format it accepts. Ask the responsible professional to confirm the interpretation and structural scope.

Save the answer in the job record. Staff guidance can change. A dated email or published bulletin gives the next reviewer a traceable basis.

Wind criteria need more than basic wind speed

Basic wind speed is only one input. The project team must also resolve risk category, exposure, topography, enclosure, mean roof height, geometry, and pressure zones. Array tilt, setbacks, gaps, and mounting height can change the selected procedure.

Rooftop systems need roof-zone mapping and array-specific pressure treatment. Corner and edge zones often govern attachment spacing. Ground mounts need terrain, structure height, row geometry, and foundation reactions. Canopies need open-building behavior, roof geometry, frame action, and foundation design.

Special wind regions require care. The adopted map or tool may direct the user to a local authority or study. Coastal work may add wind-borne debris requirements. Florida work can also involve High-Velocity Hurricane Zone rules. The HVHZ glossary explains that separate jurisdictional layer.

A wind lookup should therefore capture more than a number. Save its standard edition, coordinates, risk category, source, and any warning note. Then document the engineering choices made after the lookup.

The wind-tunnel versus code-based guide explains when a prescriptive code path may not fit the geometry. The responsible professional must select that path.

Snow criteria need more than ground snow load

Ground snow load is also a starting input. The structural design may need flat-roof snow, sloped-roof effects, exposure, thermal effects, importance, drifting, sliding snow, and unbalanced loading. Rain-on-snow or local case-study rules may also apply.

Elevation can change snow conditions across a short distance. A state table cannot capture that variation. Mountain jurisdictions often use local maps, elevation tables, or site-specific studies. If a hazard source returns a case-study flag, the flag is not a project value. It starts another source check.

Solar arrays introduce geometric questions. Elevated rows can collect drift. Adjacent roof steps can create drift zones. Sliding snow can load lower roofs, walkways, or equipment. Tilted modules may shed snow unevenly. Ballasted systems also add permanent weight before snow is considered.

Our snow-region solar design guide covers layout and structural choices after the source is confirmed. Keep the hazard lookup and the array calculation as separate records.

How to use the state routing matrix

Use the matrix during intake, not after drafting. Open the linked ICC state record first, unless the row directs you to the AHJ. ICC pages summarize adoption conditions and point toward agencies. They do not replace enacted code text.

Then answer the row’s project question. It identifies a common jurisdictional fork, not a complete checklist. Continue through the four-record process before entering any value into structural software.

Every value cell says Unresolved until project lookup. That wording is deliberate. The table must remain safe when codes change, when projects cross county lines, and when two structures share a state.

FEMA also maintains building code adoption tracking. Use it as national context and a cross-check. It does not replace state law or AHJ confirmation.

Solar wind and snow load source path by state

State	Start with	Project-specific question	Wind and snow values
Alabama	ICC Alabama record, then AHJ	Which state rules and local adoption apply to this address?	Unresolved until project lookup
Alaska	ICC Alaska record, then AHJ	Is the site under state, municipal, or deferred jurisdiction?	Unresolved until project lookup
Arizona	AHJ first, then ICC Arizona record	Which local edition and amendments control this address?	Unresolved until project lookup
Arkansas	ICC Arkansas record, then AHJ	Do state minimums or a local ordinance govern this project?	Unresolved until project lookup
California	ICC California record, then AHJ	Which Title 24 cycle and local amendments are effective?	Unresolved until project lookup
Colorado	AHJ first, then ICC Colorado record	Which local edition and accepted snow source control?	Unresolved until project lookup
Connecticut	ICC Connecticut record, then AHJ	Which state code and local administrative requirements apply?	Unresolved until project lookup
Delaware	AHJ first, then ICC Delaware record	Which county or city adoption governs the site?	Unresolved until project lookup
District of Columbia	ICC District record, then agency	Which DC code cycle and agency interpretations apply?	Unresolved until project lookup
Florida	ICC Florida record, then AHJ	Which Florida code, HVHZ, and product-approval path applies?	Unresolved until project lookup
Georgia	ICC Georgia record, then AHJ	Which state amendments and local enforcement notes control?	Unresolved until project lookup
Hawaii	ICC Hawaii record, then county	Which county amendments and island exposure conditions apply?	Unresolved until project lookup
Idaho	ICC Idaho record, then AHJ	Which state rules and local snow criteria apply?	Unresolved until project lookup
Illinois	ICC Illinois record, then AHJ	Is the controlling edition state-set, locally adopted, or both?	Unresolved until project lookup
Indiana	ICC Indiana record, then AHJ	Which statewide code and project classification control?	Unresolved until project lookup
Iowa	ICC Iowa record, then AHJ	Which state or local adoption covers the property?	Unresolved until project lookup
Kansas	AHJ first, then ICC Kansas record	Which city or county edition and amendments control?	Unresolved until project lookup
Kentucky	ICC Kentucky record, then AHJ	Which state code and local review process apply?	Unresolved until project lookup
Louisiana	ICC Louisiana record, then AHJ	Which state code, coastal wind, and flood overlays apply?	Unresolved until project lookup
Maine	ICC Maine record, then AHJ	Does the statewide framework or local enforcement path govern?	Unresolved until project lookup
Maryland	ICC Maryland record, then local jurisdiction	Which county amendments and coastal criteria apply?	Unresolved until project lookup
Massachusetts	ICC Massachusetts record, then AHJ	Which state code edition and specialized amendments apply?	Unresolved until project lookup
Michigan	ICC Michigan record, then AHJ	Which state code and local administrative requirements control?	Unresolved until project lookup
Minnesota	ICC Minnesota record, then AHJ	Which state snow criteria and local amendments apply?	Unresolved until project lookup
Mississippi	ICC Mississippi record, then AHJ	Does the site fall under state requirements or local adoption?	Unresolved until project lookup
Missouri	AHJ first, then ICC Missouri record	Which local code edition and amendments govern?	Unresolved until project lookup
Montana	ICC Montana record, then AHJ	Which state program and local snow source apply?	Unresolved until project lookup
Nebraska	ICC Nebraska record, then AHJ	Which state minimum and local edition govern this address?	Unresolved until project lookup
Nevada	ICC Nevada record, then AHJ	Which local amendments and elevation-based criteria apply?	Unresolved until project lookup
New Hampshire	ICC New Hampshire record, then AHJ	Which state code and local enforcement notes apply?	Unresolved until project lookup
New Jersey	ICC New Jersey record, then agency	Which Uniform Construction Code edition and bulletin apply?	Unresolved until project lookup
New Mexico	ICC New Mexico record, then AHJ	Which state code and local high-elevation criteria apply?	Unresolved until project lookup
New York	ICC New York record, then AHJ	Does the Uniform Code or New York City code control?	Unresolved until project lookup
North Carolina	ICC North Carolina record, then AHJ	Which code is effective after the adoption schedule changes?	Unresolved until project lookup
North Dakota	ICC North Dakota record, then AHJ	Which state framework and local adoption control?	Unresolved until project lookup
Ohio	ICC Ohio record, then AHJ	Which state code track applies to this occupancy?	Unresolved until project lookup
Oklahoma	ICC Oklahoma record, then AHJ	Which state rules and local amendments control?	Unresolved until project lookup
Oregon	ICC Oregon record, then AHJ	Which state specialty code and local snow source apply?	Unresolved until project lookup
Pennsylvania	ICC Pennsylvania record, then AHJ	Which Uniform Construction Code path and local review apply?	Unresolved until project lookup
Rhode Island	ICC Rhode Island record, then AHJ	Which state code and coastal exposure questions apply?	Unresolved until project lookup
South Carolina	ICC South Carolina record, then AHJ	Which state edition, coastal zone, and local process apply?	Unresolved until project lookup
South Dakota	ICC South Dakota record, then AHJ	Which local adoption and accepted snow source control?	Unresolved until project lookup
Tennessee	ICC Tennessee record, then AHJ	Which state or local code path covers the project?	Unresolved until project lookup
Texas	AHJ first, then ICC Texas record	Which local edition and coastal provisions govern the site?	Unresolved until project lookup
Utah	ICC Utah record, then AHJ	Which state code, snow study, and elevation criteria apply?	Unresolved until project lookup
Vermont	ICC Vermont record, then AHJ	Which state safety code and local authority apply?	Unresolved until project lookup
Virginia	ICC Virginia record, then AHJ	Which statewide code edition and local administration apply?	Unresolved until project lookup
Washington	ICC Washington record, then AHJ	Which state code, local amendments, and snow source apply?	Unresolved until project lookup
West Virginia	ICC West Virginia record, then AHJ	Which state code and local enforcement arrangement apply?	Unresolved until project lookup
Wisconsin	ICC Wisconsin record, then AHJ	Which state code track and local snow criteria apply?	Unresolved until project lookup
Wyoming	AHJ first, then ICC Wyoming record	Which local edition and accepted mountain snow source control?	Unresolved until project lookup

The matrix answers where to start. It does not answer what to calculate. Confirm the source path again if the address, structure, occupancy, or permit authority changes.

Follow one traceable project workflow

Consider a commercial rooftop project entering preliminary design. The sales record identifies a city and ZIP code. That information is not enough for a structural load basis.

The permit coordinator first confirms the parcel and street address. The coordinator also identifies the city or county that issues the building permit. A mailing city can differ from the permitting authority.

Next, the team opens the state routing source. It follows the links to the current adoption record and local ordinance. The record identifies the enforceable building code and its referenced load standard. Any local amendment is saved beside that record.

The hazard lookup uses the verified coordinates and the selected standard edition. The saved report identifies its inputs and lookup date. If the output contains a warning or case-study flag, the team does not guess. It sends a focused question to the AHJ.

The field survey then supports the engineering choices. Photographs and measurements establish roof height, slope, parapets, surrounding terrain, and supporting framing. The array layout shows module position, tilt, gaps, and roof zones.

The responsible professional reviews those records together. That review converts hazard information into a project design basis. Calculations then apply the selected wind and snow procedures to the actual structure.

The cover sheet should preserve the path. It lists the code edition, standard edition, risk category, source date, and local amendment. It also identifies assumptions that still require field verification.

If the AHJ later requests another edition, the team reopens the basis. It does not replace one number and leave the remaining calculations unchanged. Edition changes can affect maps, coefficients, combinations, and detailing.

Use a status for every input

A simple status field prevents assumptions from hiding inside a model. Use confirmed, pending, or not applicable for each input. Add the source and reviewer beside every confirmed field.

Pending fields should have an owner and next action. For example, the permit coordinator may own an AHJ snow-source question. The site survey team may own a missing parapet height. The structural reviewer may own the exposure decision.

Do not label an input confirmed because software accepted it. Software checks data type and range. It does not prove jurisdictional authority or field accuracy.

Keep hazards separate from design results

The hazard file records environmental criteria for a location and edition. The structural calculation applies those criteria to geometry and materials. The drawing presents the final design notes and details.

Those records should agree, but they should remain distinct. This separation makes revisions easier to audit. It also helps a reviewer find the origin of each stated criterion.

Avoid five common source failures

Reusing a nearby project

A nearby project may sit under another AHJ, elevation band, exposure, or code cycle. Use it only as a workflow example. Repeat the source checks for the new address.

Selecting an edition by habit

A design office may prefer one ASCE edition. Preference does not establish enforcement. Start with the adopted code and documented amendments.

Treating a map screenshot as evidence

A cropped image may omit the legend, edition, coordinates, and warning notes. Save the generated report or full official record. Name the file so another reviewer can trace it.

Turning an AHJ conversation into a universal rule

Staff guidance answers a specific question for a specific project. Record the date, contact, question, and response. Do not extend that answer to another jurisdiction without confirmation.

Mixing source facts with engineering judgment

The source may provide a hazard parameter. Exposure, drift geometry, load paths, and connection adequacy require professional judgment. Label each item by its source and decision owner.

These failures have one pattern. The final number loses its chain of evidence. The four-record method keeps that chain visible from intake through review.

Apply different checks to each solar structure

The four-record method stays constant. The engineering questions change with the structure.

Rooftop arrays

Confirm the roof geometry, mean roof height, edge dimensions, parapets, and array position. Document framing size, spacing, span, species, grade, and condition. Identify the roof covering and attachment method. Map the modules into the applicable pressure zones.

Snow review must address roof slope, array height, adjacent steps, sliding paths, and obstructions. Existing drift zones can govern before the array adds another obstruction. A field survey should capture the details needed for the structural calculation report.

Ground-mounted arrays

Confirm row geometry, height, tilt range, terrain, and exposure. Trackers require their operating and stow assumptions. Fixed-tilt structures still need wind direction, shielding, and load-path decisions.

Foundation design also needs geotechnical inputs. Wind and snow reactions do not prove pile, pier, or ground-screw capacity. Corrosion, frost, expansive soils, and groundwater can affect the selected foundation.

Solar canopies and carports

Canopies combine array loading with an occupied structure below. Open sides can create pressure on both surfaces. Frame action transfers forces through beams, columns, connections, base plates, and foundations.

Vehicle clearance and impact protection add coordination needs. Drainage can also affect snow and ice behavior. Use the solar carport design guide to frame those inputs before analysis.

Structural intake checklist for permit teams

Collect the following records before structural modeling starts:

• Full street address, parcel identifier, latitude, longitude, and site elevation.
• Project type, occupancy, ownership, and permit authority.
• Adopted building code, referenced ASCE 7 edition, and local amendment record.
• Risk category and the reason for its selection.
• Dated hazard report with coordinates and selected edition.
• Published state or local wind map, snow map, bulletin, or case-study direction.
• AHJ response for any special region, case-study flag, or conflicting source.
• Roof plan, elevations, sections, dimensions, and parapet details.
• Array geometry, tilt, mounting height, setbacks, and row spacing.
• Module, rail, attachment, tracker, or canopy product data.
• Field measurements and clear photographs of the supporting structure.
• Existing framing data, material properties, connection details, and observed damage.
• Geotechnical information for ground mounts and canopy foundations.
• Responsible-professional confirmation of assumptions and calculation method.

Mark unknown fields as unknown. Do not fill them with values from a nearby job. An explicit open item is easier to manage than a hidden assumption.

Use a controlled criteria sheet. Give each source a title, owner, date, and file path. The STAAD.Pro report guide explains how calculation outputs fit the wider review package.

Reopen the load basis when project facts change

The load basis is not a one-time intake note. Recheck it after any change that affects jurisdiction, hazard, geometry, or load path.

Common triggers include:

• The permit address or coordinates change.
• The AHJ identifies a different adopted edition.
• A state or local code cycle becomes effective.
• The building occupancy or risk category changes.
• The array moves into a roof edge or corner zone.
• Module dimensions, tilt, or mounting height change.
• A parapet, adjacent roof, or rooftop unit is added to the model.
• The site survey changes roof height, framing, or exposure assumptions.
• A case-study region or local snow map is identified.
• The mounting product or attachment schedule changes.
• The AHJ requests another load case, note, or document.
• The responsible professional revises an engineering assumption.

Record the revision. State what changed, which calculations were rerun, and which sheets were updated. Do not overwrite the old hazard report without a trace.

Turn the confirmed criteria into a reviewable package

Heaven Designs can prepare structural calculation support and coordinated solar permit drawings from confirmed project inputs. The scope depends on the site, jurisdiction, and responsible-professional requirements. Review our solar civil and structural engineering service and solar permit design service for the available drawing support.

Send the address, AHJ, adopted code information, site survey, array layout, and equipment data through the project contact form. Identify every unresolved load question in the message. The team can then define the required inputs and review path without guessing.

No drawing service can guarantee approval. The AHJ controls permitting, and the responsible professional controls the engineering judgment. A complete source record gives both reviewers a clearer package.

Frequently asked questions

What is the wind speed for solar panels in my state?

There is no single safe statewide answer. Use the exact address, adopted standard edition, risk category, and accepted hazard source. Then confirm local amendments, special wind regions, exposure, and AHJ requirements. The resulting speed is only one input to the pressure calculation.

Can I use the newest ASCE 7 edition for every project?

No. The governing edition comes from the enforceable building code and its amendments. A newer published edition does not automatically replace the locally adopted edition. Confirm the edition before running the hazard lookup or calculations.

Does the ASCE Hazard Tool provide final solar design loads?

No. It provides hazard information for selected locations and standards. The structural professional still resolves exposure, geometry, pressure zones, load combinations, and the structure’s response. Local criteria can add another source layer.

What should I do when a snow source says case study?

Do not turn the flag into a value. Ask the AHJ which local map, study, table, or site-specific method it accepts. Record the answer and have the responsible professional confirm its use.

Does the International Building Code set one load for each state?

No. The International Building Code provides a model-code framework. Jurisdictions adopt editions and amendments through law. Project hazards and structural conditions still vary by location.

Are residential solar projects always governed by the IRC?

No. The applicable code depends on the building, scope, and local adoption. Confirm whether the International Residential Code, IBC, or another state code controls the project.

Who should approve the final wind and snow criteria?

The AHJ confirms its permitting requirements. The responsible structural professional confirms the engineering basis and calculations. Both roles matter, and one does not replace the other.

How often should this state matrix be reviewed?

Review the source path before every project and after any adoption change. This article should receive a formal source review by January 15, 2027. Earlier review is needed when a state or jurisdiction changes its code.