New Hanover County North Carolina | 130-140 mph Design Wind Speed | Exposure Category C Coastal/B Inland | NC State Building Code | ASCE 7-22
Calculate Wilmington Wind Loads Now →Wilmington, located in New Hanover County, North Carolina, is a historic port city positioned on the Cape Fear River near the Atlantic Ocean coast. Due to its coastal location and hurricane exposure, Wilmington requires substantial wind load design with wind speeds of approximately 130-140 mph (3-second gust) for Risk Category II structures, based on ASCE 7-22 wind speed maps and the city's position in a high-risk hurricane zone.
Wilmington has experienced multiple severe hurricanes in recent history, most notably Hurricane Florence (2018), which made landfall near Wrightsville Beach and caused catastrophic flooding and wind damage throughout the region. The city also has historic storm references including Hurricane Hazel (1954), one of the most devastating hurricanes in North Carolina history. These events underscore the critical importance of proper wind load engineering in Wilmington and surrounding coastal communities.
Design Wind Speed (Risk Category II): 130-140 mph (3-second gust, varies by location)
Design Wind Speed (Risk Category III): ~145-155 mph
Design Wind Speed (Risk Category IV): ~155-165 mph
Exposure Category: C (coastal areas), B (inland neighborhoods)
Building Code: North Carolina State Building Code (adopts IBC)
Wind Load Standard: ASCE 7-22
Hurricane History: Florence (2018), Hazel (1954), and numerous other storms
Port City: Port of Wilmington on Cape Fear River
Wilmington's design wind speeds of 130-140 mph are derived from ASCE 7-22 wind speed maps for the North Carolina coastal region. This velocity range accounts for the city's position on the Atlantic hurricane corridor and its history of direct and near-direct hurricane impacts. The Cape Fear River estuary and coastal geography create varying wind exposures throughout the region.
The exact wind speed for a specific Wilmington project depends on precise location. Coastal areas near Wrightsville Beach, Carolina Beach, and Kure Beach typically require the higher end of the range (135-140 mph) due to direct ocean exposure and minimal terrain protection, while inland neighborhoods may use the lower end (130-135 mph). The WindLoadCalc.com calculator automatically determines the correct velocity based on your project's zip code or address.
Wilmington's coastal geography significantly influences wind load requirements:
Hurricane Florence made landfall near Wrightsville Beach in September 2018 as a Category 1 hurricane (at landfall), bringing sustained winds of 90 mph and catastrophic rainfall. While Florence weakened before landfall, its slow movement caused unprecedented flooding throughout the Cape Fear region. The storm demonstrated that wind load design must be coupled with flood resilience in coastal North Carolina.
Hurricane Hazel (1954) remains the benchmark hurricane for North Carolina's coast, making landfall near the NC/SC border as a Category 4 storm with sustained winds of 130 mph. Hazel destroyed nearly every building at Carolina Beach and Wrightsville Beach and caused widespread damage in Wilmington. These historic events inform modern building codes and wind load requirements throughout the region.
Calculating wind loads for Wilmington projects requires following ASCE 7-22 methodology with North Carolina State Building Code requirements. The fundamental velocity pressure equation is:
qz = 0.00256 Kz Kzt Kd Ke V²
For a typical Wilmington coastal project with V = 135 mph and Exposure C conditions, the resulting pressures are substantial and require proper engineering. A Wrightsville Beach project with:
Results in a velocity pressure of approximately qz = 42.5 psf—substantial wind loads requiring proper structural design, anchoring, and connection details.
All Wilmington projects must comply with the North Carolina State Building Code, which adopts the International Building Code (IBC) with North Carolina-specific amendments. Key requirements include:
Coastal Areas (Wrightsville Beach, Carolina Beach): Design wind speed 135-140 mph, Exposure Category C required, potential V-Zone requirements
Inland Wilmington: Design wind speed 130-135 mph, Exposure Category B may be applicable with proper terrain justification
Key Takeaway: Location within New Hanover County significantly affects wind load requirements and exposure categories
Wilmington 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 | Wilmington Design Wind Speed | Building Types |
|---|---|---|
| Risk Category I | ~120-130 mph | Agricultural facilities, temporary structures, minor storage |
| Risk Category II | 130-140 mph | Residential, commercial, most standard occupancies |
| Risk Category III | ~145-155 mph | Schools, assembly >300, substantial hazardous materials |
| Risk Category IV | ~155-165 mph | Hospitals, fire stations, emergency shelters, EOCs |
Wilmington projects require careful exposure category determination based on location and surrounding terrain:
Engineers must carefully evaluate the terrain within the required upwind distance (typically 1 mile for Exposure C, 2600 feet for Exposure B) to properly determine the applicable exposure category. Coastal areas with direct ocean exposure typically require Exposure C, while inland wooded areas may qualify for Exposure B.
Wilmington/New Hanover County uses zip codes primarily in the 28401-28412 range. Wind speeds vary by location:
The WindLoadCalc.com wind load calculator automatically determines the correct wind speed and exposure category recommendations when you enter any Wilmington/New Hanover County zip code or address, using ASCE 7-22 wind speed maps and local terrain analysis.
WindLoadCalc.com automatically handles all Wilmington/New Hanover County requirements including location-specific wind velocities (130-140 mph range), appropriate Exposure Category recommendations, Risk Category adjustments, and component pressure coefficients. Simply enter your Wilmington project address or zip code for instant, accurate calculations.
Calculate Wilmington Wind Loads Now →All wind load calculations for Wilmington building permits must be prepared by or under the direct supervision of a Professional Engineer (PE) or Architect licensed in North Carolina. The sealed calculations must include:
Engineers, architects, and contractors should reference these official resources for Wilmington wind load compliance:
The wind load calculator at WindLoadCalc.com automatically applies all Wilmington-specific requirements:
WindLoadCalc.com provides instant, accurate wind load calculations for Wilmington/New Hanover County projects. Our software automatically handles location-specific wind velocities (130-140 mph), appropriate Exposure Category recommendations, and generates PE-ready reports for building permit submission.
Try Wilmington Wind Load Calculator →