OREGON · MULTNOMAH COUNTY
Portland Wind Load Requirements
Where the Willamette Valley meets the Columbia River, Pacific Northwest winter storms and Columbia Gorge channeling shape design under the Oregon Structural Specialty Code.
WILLAMETTE VALLEY · PACIFIC NW
Gorge Channeling & Pacific Storms
Portland's base wind is moderate, but the Columbia River Gorge and offshore winter systems create directional effects flat maps alone miss.
Columbia Gorge Channeling
The Gorge cuts a sea-level passage through the Cascades, accelerating strong east winds in winter and westerlies in summer toward east Portland.
DIRECTIONALPacific Winter Windstorms
Fall and winter frontal systems off the Pacific drive sustained westerly winds and gusts that govern cladding and roofing pressures.
SEASONALExposure B — Urban Core
Downtown, the close-in eastside and the West Hills neighborhoods generally qualify as Exposure B under ASCE 7-22 §26.7.
URBAN/SUBURBANExposure C — River & Gorge
Open ground along the Columbia and Willamette rivers, the airport vicinity and Gorge-facing east Portland can push sites toward Exposure C.
SITE-SPECIFICWest Hills slopes, ridges and escarpments can carry a topographic factor (Kzt) above 1.0 near crests, returning toward 1.0 away from the feature. Valley floors typically remain Kzt = 1.0.
MULTNOMAH COUNTY · COMPLIANCE
What a Portland Permit Must Satisfy
The inputs and authorities a Portland submission has to clear under the Oregon Structural Specialty Code.
Design Wind Speed
Risk Category II ranges 100–110 mph (3-second gust); higher Risk Categories read a longer-MRI map. Verify the value for your exact site.
100–110 MPHCode & Edition
The Oregon Structural Specialty Code (OSSC) adopts the IBC with Oregon amendments and references ASCE 7-22 for wind.
OSSC · ASCE 7-22Exposure Category
Resolve Exposure B vs. C from surrounding roughness; river corridors and Gorge-facing sites can shift the determination per §26.7.
PER §26.7Topographic Factor
Run a Kzt analysis for West Hills ridges and escarpments per ASCE 7-22 §26.8 — don't assume Kzt = 1.0 on elevated slopes.
§26.8 KztPE Sealing
Structural calculations must be stamped and signed by an Oregon-licensed Professional Engineer through OSBEELS.
PE REQUIREDPermit Authority
The City of Portland Bureau of Development Services (BDS) reviews structural calculations and issues building permits.
PORTLAND BDSOREGON · OFFICIAL RESOURCES
Authorities & Statewide References
Official Portland and Oregon sources, plus statewide wind-load context.
Portland Bureau of Development Services
Building permits, plan review and structural requirements.
OFFICIALOregon Building Codes Division
Statewide OSSC adoption and code enforcement.
OFFICIALOregon State Board of Engineers
OSBEELS licensure of Professional Engineers.
OFFICIALOregon Wind Load Requirements
Statewide OSSC and ASCE 7-22 wind-load context.
STATE HUBWind Speed by Location
Look up design wind speeds across the country.
MAP TOOLWind Load Calculators
Run Portland-specific ASCE 7-22 calculations and PE-ready reports.
CALCULATEASCE 7-22 · PORTLAND-READY
Automate Your Portland Wind Loads
Enter a Portland address or zip and get the 100–110 mph velocity range, Exposure B/C selection, Gorge and topographic guidance, and PE-ready reports for BDS submission.