Oklahoma County, OK | 115-125 mph Design Wind Speed | HEART OF TORNADO ALLEY | Oklahoma Uniform Building Code (IBC) | Exposure B/C
Calculate Oklahoma City Wind Loads Now →Oklahoma City, located in Oklahoma County, Oklahoma, has elevated wind load requirements that reflect its position in the HEART OF TORNADO ALLEY—the most tornado-prone region in the United States. Oklahoma uses the Oklahoma Uniform Building Code Commission (OUBCC) which adopts the International Building Code (IBC) with state-specific amendments. Design wind speeds for Risk Category II structures typically range from 115-125 mph (3-second gust) based on ASCE 7-22 wind speed maps.
These requirements exist because Oklahoma City experiences the highest frequency of violent tornadoes anywhere on Earth. The May 2013 EF5 Moore tornado—one of the most destructive tornadoes in recorded history—killed 24 people and caused $2+ billion in damage just 8 miles south of downtown Oklahoma City. The May 1999 Bridge Creek-Moore F5 tornado produced the highest wind speeds ever recorded on Earth at 302±22 mph. Oklahoma City averages 11+ tornadoes per year within Oklahoma County alone, with frequent severe thunderstorms, derechos, and extreme convective wind events throughout spring and early summer.
Design Wind Speed (Risk Category II): 115-125 mph (3-second gust, varies by location)
Design Wind Speed (Risk Category III): ~130-140 mph
Design Wind Speed (Risk Category IV): ~140-150 mph
Exposure Category: B (urban areas), C (open plains/developing suburbs)
Building Code: Oklahoma Uniform Building Code (adopts IBC)
Wind Load Standard: ASCE 7-22 (current edition)
County: Oklahoma County
Weather Risks: EXTREME tornado risk, May 2013 EF5 Moore tornado, May 1999 Bridge Creek-Moore F5, severe thunderstorms, derechos
Oklahoma City's design wind speed of 115-125 mph for Risk Category II structures reflects the city's position in the absolute epicenter of Tornado Alley—the most tornado-prone location on Earth. While ASCE 7 wind speeds are based on synoptic (large-scale) wind events rather than tornadoes, Oklahoma City's elevated base wind speed accounts for:
Oklahoma City's tornado climatology is unprecedented globally. The city experiences more violent (EF4/EF5) tornadoes per capita than any other major metropolitan area. The May 2013 Moore tornado remains one of the costliest tornadoes in U.S. history and prompted widespread discussion of building code enhancements and safe room requirements for schools.
Calculating wind loads for Oklahoma City projects requires following ASCE 7-22 methodology as adopted by the Oklahoma Uniform Building Code. The fundamental velocity pressure equation is:
qz = 0.00256 Kz Kzt Kd Ke V²
For Oklahoma City with V = 120 mph (typical central Oklahoma City) and standard conditions, the resulting pressures are significantly elevated. An Oklahoma City project with:
Results in a velocity pressure of approximately qz = 26.6 psf—substantially higher than non-severe-weather regions and reflecting Oklahoma City's extreme tornado exposure.
For open areas and developing suburbs using Exposure C (northern Oklahoma City suburbs, Edmond, Moore), the pressures increase significantly due to the higher velocity pressure coefficient for open terrain exposure typical of the Great Plains.
Oklahoma uses the Oklahoma Uniform Building Code Commission (OUBCC) which adopts the International Building Code (IBC) with state-specific amendments. Oklahoma City also adds local amendments specific to Oklahoma County conditions.
Key Oklahoma City building code considerations:
You can access Oklahoma City building permits and requirements through the City of Oklahoma City Development Services Department.
Oklahoma City projects must be classified into Risk Categories per ASCE 7-22 Table 1.5-1. Higher risk categories require increased design wind speeds:
| Risk Category | Oklahoma City Design Wind Speed | Building Types |
|---|---|---|
| Risk Category I | ~110-115 mph | Agricultural facilities, temporary structures, minor storage |
| Risk Category II | 115-125 mph | Residential, commercial, most standard occupancies |
| Risk Category III | ~130-140 mph | Schools (with tornado shelter requirements), assembly >300, substantial hazardous materials |
| Risk Category IV | ~140-150 mph | Hospitals, fire stations, emergency shelters, EOCs (tornado shelter requirements) |
Oklahoma City projects require careful Exposure Category determination based on surrounding terrain and development density:
Exposure Category B (Urban): Central Oklahoma City, established neighborhoods, and dense urban areas qualify as Exposure B due to numerous buildings, trees, and other obstructions. Exposure B assumes urban and suburban areas with buildings having heights generally less than 30 feet extending more than 800 feet upwind. This applies to downtown Oklahoma City, Midtown, Nichols Hills, and established inner suburbs.
Exposure Category C (Open Plains/Developing Areas): Much of the Oklahoma City metropolitan area—particularly developing suburbs in Moore, Norman, Edmond, Yukon, Mustang, and northern Oklahoma County—qualifies as Exposure C. The Great Plains topography features open terrain with scattered obstructions. Exposure C produces significantly higher wind pressures than Exposure B and is the more common exposure category for Oklahoma City area projects.
Engineering Judgment Required: The transition between Exposure B and C in Oklahoma City's rapidly developing suburbs requires professional engineering judgment. When in doubt, the more conservative Exposure C should be used, which is appropriate for most Oklahoma City area locations given the open plains terrain.
Oklahoma City's wind load requirements are fundamentally driven by the city's position in the HEART OF TORNADO ALLEY—the most tornado-prone region on Earth:
May 2013 EF5 Moore Tornado: On May 20, 2013, an EF5 tornado struck Moore, Oklahoma (8 miles south of downtown Oklahoma City) producing winds exceeding 210 mph, a width of 1.3 miles, and a 17-mile path. The tornado killed 24 people (including 7 children at Plaza Towers Elementary School), injured 212+, destroyed 1,150+ homes, damaged 2,400+ additional structures, and caused $2+ billion in damage. This event prompted nationwide discussion of tornado shelter requirements in schools and led to enhanced building code provisions in Oklahoma.
May 1999 Bridge Creek-Moore F5 Tornado: On May 3, 1999, an F5 tornado tracked through Bridge Creek and Moore producing the highest wind speed ever recorded on Earth—302±22 mph measured via Doppler on Wheels (DOW) mobile radar. The tornado killed 36 people, injured 583, destroyed 1,800+ homes, and caused $1+ billion in damage (1999 dollars). This remains the benchmark for extreme tornado wind speeds.
Tornado Frequency: Oklahoma County averages 11+ tornadoes per year—the highest frequency in the United States. Oklahoma City proper has been struck by violent tornadoes in 1999, 2003, 2010, 2013, and numerous other years. The peak tornado season runs from April through June, with May being the most active month.
Severe Thunderstorm Winds: Beyond tornadoes, Oklahoma City experiences frequent severe thunderstorms producing damaging straight-line winds exceeding 70-90 mph. Derecho events (organized lines of severe thunderstorms) can produce widespread wind damage across the Oklahoma City metro area.
Oklahoma City zip codes span a large geographic area with relatively consistent wind speed requirements. Common Oklahoma City area zip codes include:
The WindLoadCalc.com wind load calculator automatically applies the appropriate Oklahoma City wind speed based on your specific zip code or street address, accounting for local terrain conditions and exposure.
Wind load calculations for Oklahoma City building permits have varying PE requirements depending on building type and complexity:
Oklahoma Professional Engineers must be licensed through the Oklahoma State Board of Licensure for Professional Engineers and Land Surveyors.
Engineers, architects, and contractors should reference these official resources for Oklahoma City wind load compliance:
The wind load calculator at WindLoadCalc.com automatically applies all Oklahoma City-specific requirements:
WindLoadCalc.com automatically handles all Oklahoma City-specific requirements including the 115-125 mph design velocity, appropriate Exposure Category selection (B/C), Risk Category adjustments, and component pressure coefficients. Simply enter your Oklahoma City project address or zip code for instant, accurate calculations.
Calculate Oklahoma City Wind Loads Now →Oklahoma City's wind load requirements reflect the most extreme tornado risk in the United States:
| City | Design Wind Speed (Risk Cat II) | Tornado Risk |
|---|---|---|
| Oklahoma City, OK | 115-125 mph | EXTREME - May 2013 EF5 Moore, May 1999 F5 Bridge Creek-Moore |
| Dallas, TX | 105-115 mph | Moderate - Edge of Tornado Alley |
| Kansas City, MO/KS | 110-120 mph | High - Tornado Alley |
| Wichita, KS | 115-120 mph | High - Tornado Alley |
Oklahoma City represents the absolute epicenter of violent tornado activity globally. The combination of 115-125 mph base wind speeds, Exposure C open plains terrain, and extreme tornado frequency makes Oklahoma City one of the most demanding wind load design environments in the United States.
The Oklahoma City metropolitan area includes numerous suburbs and cities with similar wind load requirements:
Engineers working across the Oklahoma City metro area should recognize the consistently high tornado risk and elevated wind load requirements throughout the region. The May 2013 Moore tornado and May 1999 Bridge Creek-Moore tornado both tracked through multiple communities, demonstrating the widespread nature of tornado risk in the Oklahoma City metropolitan area.
WindLoadCalc.com provides instant, accurate wind load calculations for Oklahoma City projects. Our software automatically handles the 115-125 mph velocity range, Exposure B/C determination, and generates PE-ready reports for building permit submission in the HEART OF TORNADO ALLEY.
Try Oklahoma City Wind Load Calculator →