ARKANSAS · ASCE 7-16 / 7-22 · SOUTHERN TORNADO ALLEY

Arkansas Wind Load Requirements

A voluntary state in the heart of southern Tornado Alley — major cities and the fast-growing Northwest Arkansas corridor adopt the IBC with ASCE 7 wind provisions.

105–115MPH BASIC WIND, RISK II
39TORNADOES PER YEAR (AVG)
7-16ASCE EDITION ADOPTED
VoluntarySTATEWIDE REQUIREMENT

CODE FRAMEWORK

Adopted Code & ASCE 7 Edition

Arkansas has no mandatory statewide building code — each municipality decides. Major jurisdictions adopt the 2018/2021 IBC referencing ASCE 7-16; rural counties may enforce none.

2018 / 2021 IBC

Adopted code, varies by jurisdiction.

IBC

ASCE 7-16

Referenced wind standard across cities.

WIND STD

Voluntary State

PE-sealed calcs not required statewide.

VOLUNTARY

ASCE 7-22

Newer edition adds Ch 32 tornado loads.

CH 32
JurisdictionAdopted CodeWind StandardNotes
Little Rock2021 IBCASCE 7-16State capital requirements
Fayetteville2021 IBCASCE 7-16University zone, rapid growth
Bentonville2021 IBCASCE 7-16Walmart HQ, corporate campus
Rogers2018 IBCASCE 7-16NW Arkansas growth corridor
Fort Smith2018 IBCASCE 7-16Western Arkansas hub

Rural Arkansas

Many rural counties have no building codes. The eastern delta is especially vulnerable — little enforcement despite high tornado risk. Wind load analysis is voluntary but strongly recommended.

WIND SPEED & TORNADO CONTEXT

Basic Wind Speed & Tornado Hazard

Arkansas basic wind speeds run 105–115 mph for Risk Category II per ASCE 7-16/7-22; the eastern delta tends slightly higher. The state averages 39 tornadoes per year, with dangerous nocturnal events more common than states to the north.

RegionRisk Cat IIRisk Cat IIIRisk Cat IV
Little Rock Metro110 mph115 mph120 mph
NW Arkansas (Fayetteville)105 mph110 mph115 mph
Delta Region (East)115 mph120 mph125 mph
Southwest Arkansas110 mph115 mph120 mph

Nocturnal Tornadoes

Occur more often here than further north — a key life-safety driver.

HIGH RISK

ASCE 7-22 Chapter 32

Adds tornado-load provisions for Risk Category III & IV buildings — designers should evaluate them qualitatively where 7-22 applies.

RISK III / IV

Varied Terrain

Flat delta (Exposure C) to Ozark and Ouachita topography where Kzt may apply.

EXPOSURE

Regional Exposure

Delta (East): open Exposure C · Central Arkansas: mixed B/C · Ozark Plateau (NW): topographic Kzt effects · Ouachita Mountains: complex terrain needing careful exposure analysis.

WHEN CALCULATIONS ARE NEEDED

When Wind Load Calculations Apply

Arkansas is voluntary, but calculations are recommended or required across these common situations.

Commercial Buildings

Little Rock, NW Arkansas and other code-adopting cities.

REQUIRED

Risk Cat III / IV

Schools, hospitals, emergency facilities.

ESSENTIAL

Corporate Campuses

Walmart, Tyson and JB Hunt facilities.

INDUSTRY

Poultry & Ag Structures

Large-span chicken houses and equipment buildings.

SPAN

Solar Installations

Ground-mount and rooftop systems.

UPLIFT

Insurance Requirements

Many insurers require sealed engineering.

UNDERWRITING

RISK CATEGORIES

Risk Category Drives the Wind Map

Higher risk category selects a longer return-period wind map — higher design speed and loads. There is no fixed multiplier between categories.

Risk Category I

Low hazard — minor agricultural and storage.

300-YR MRI

Risk Category II

Standard occupancy — homes, offices, retail.

700-YR MRI

Risk Category III

Assembly, schools — substantial hazard.

1,700-YR MRI

Risk Category IV

Essential — hospitals, fire/police, shelters.

3,000-YR MRI

Historic Arkansas Tornadoes

Vilonia–Mayflower (Apr 27, 2014, EF4, 16 fatalities) · February 2008 Super Tuesday outbreak (EF4, 13 fatalities) · Jonesboro (Mar 28, 2020, EF3, 22 injuries) · Little Rock (Mar 31, 2023, EF3, 4 fatalities).

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