Arkansas Wind Load Overview
Southern Tornado Alley
Arkansas sits in the southern extension of Tornado Alley, experiencing an average of 39 tornadoes per year. The state's diverse terrain - from the Ozark Plateau to the Mississippi River delta - creates varied wind exposure conditions. Nocturnal tornadoes, which are particularly dangerous, occur more frequently in Arkansas than in states further north.
Arkansas is a voluntary wind load state, meaning PE-sealed wind load calculations are not legally required statewide. However, major cities and the rapidly growing Northwest Arkansas corridor have adopted building codes with wind load provisions.
Quick Facts
- State Requirement: Voluntary (not legally required statewide)
- Adopted Code: 2018/2021 IBC with ASCE 7-16 (varies by jurisdiction)
- Basic Wind Speed Range: 105-115 mph (Risk Category II)
- Tornado Risk: High - especially nocturnal tornadoes
- Special Provisions: Varied terrain exposure considerations
- Local Amendments: Little Rock, Fayetteville, NW Arkansas have codes
Arkansas Terrain and Exposure
Arkansas's diverse geography significantly impacts wind load design. The state transitions from the flat Mississippi River delta in the east to the Ozark and Ouachita mountains in the west and north.
Regional Exposure Variations
- Delta Region (East): Exposure C - flat, open agricultural land
- Central Arkansas: Mix of Exposure B and C depending on development
- Ozark Plateau (NW): Topographic effects (Kzt) may apply
- Ouachita Mountains: Complex terrain requires careful exposure analysis
Historic Arkansas Tornadoes
| Event | Date | Rating | Impact |
|---|---|---|---|
| Vilonia-Mayflower | April 27, 2014 | EF4 | 16 fatalities, significant damage |
| February 2008 Outbreak | February 5, 2008 | EF4 | 13 fatalities, Super Tuesday tornado |
| Jonesboro Tornado | March 28, 2020 | EF3 | 22 injuries, hospital and airport damaged |
| Little Rock Tornado | March 31, 2023 | EF3 | 4 fatalities, extensive urban damage |
Arkansas Building Code Framework
Arkansas has no mandatory statewide building code. Each municipality determines whether to adopt building codes. The Northwest Arkansas corridor (Benton and Washington counties) has seen significant code adoption due to rapid growth.
Major Jurisdiction Code Adoption
| Jurisdiction | Adopted Code | Wind Standard | Special Requirements |
|---|---|---|---|
| Little Rock | 2021 IBC | ASCE 7-16 | State capital requirements |
| Fayetteville | 2021 IBC | ASCE 7-16 | University zone, rapid growth |
| Bentonville | 2021 IBC | ASCE 7-16 | Walmart HQ, corporate campus |
| Rogers | 2018 IBC | ASCE 7-16 | NW Arkansas growth corridor |
| Fort Smith | 2018 IBC | ASCE 7-16 | Western Arkansas hub |
Rural Arkansas
Many rural Arkansas counties have no building codes. The delta region in eastern Arkansas is particularly vulnerable, with little code enforcement despite significant tornado risk. Wind load analysis is voluntary but strongly recommended.
Arkansas Wind Speed Zones
Arkansas basic wind speeds per ASCE 7-16/7-22 range from 105 mph to 115 mph for Risk Category II structures. The eastern delta region tends to have slightly higher wind speeds.
| Region | Risk Cat II | Risk Cat III | Risk Cat IV |
|---|---|---|---|
| Little Rock Metro | 110 mph | 115 mph | 120 mph |
| NW Arkansas (Fayetteville) | 105 mph | 110 mph | 115 mph |
| Delta Region (East) | 115 mph | 120 mph | 125 mph |
| Southwest Arkansas | 110 mph | 115 mph | 120 mph |
ASCE 7 Wind Load Formula
Velocity Pressure Equation
When Wind Load Calculations Are Needed
Although Arkansas is a voluntary state, wind load calculations are recommended or required in several situations:
Recommended/Required Situations
- Commercial buildings in Little Rock, NW Arkansas, and other cities
- Risk Category III/IV structures (schools, hospitals, emergency facilities)
- Corporate campus construction - Walmart, Tyson, JB Hunt facilities
- Poultry industry structures - large span buildings
- Insurance requirements - many insurers require engineering
- Solar installations - ground-mount and rooftop systems
- Agricultural structures - chicken houses, equipment buildings
Related State Guides
Explore wind load requirements for neighboring and similar states
Need Arkansas Wind Load Calculations?
Our professional ASCE 7 wind load calculators account for Arkansas's unique terrain variations, exposure conditions, and local jurisdiction requirements.
Get Wind Load Calculator