TEXAS · HARRIS COUNTY · GULF COASTAL PLAIN
Fifty miles inland, still in the hurricane's reach
Houston spreads across a flat coastal plain about 50 miles up from Galveston Bay — far enough from the shore to dodge surge maps, close enough that a major Gulf storm still arrives with hurricane-force wind.
THE INLAND-METRO THREAT
A spreading metro on an unbroken coastal plain
Nothing between Galveston Bay and Harris County slows a storm down — the land is flat, low and open, so hurricane wind drives deep inland before it weakens.
Because the plain offers no terrain to break the wind, the ASCE 7-22 maps keep Houston in the 130–140 mph Risk II band well inland of the coast.
HURRICANE-PRONE REGION · WIND-BORNE DEBRIS
Inland velocity, suburban exposure, and a debris fringe
Harris County is a hurricane-prone region: the wind speed stays elevated 50 miles in, exposure runs mostly suburban, and the wind-borne-debris line sits out toward the bay.
Why 130–140 mph Holds Inland
The flat, open coastal plain lets Gulf storms hold strength deep inland, keeping Harris County in the 130–140 mph Risk II band on the ASCE 7-22 maps.
3-SEC GUSTCitywide Exposure B
Most of Houston's dense, built-out suburbs — subdivisions, tree cover and low buildings — resolve to Exposure B under ASCE 7-22 Sec. 26.7.
SUBURBANBay-Side Exposure C
Sites toward Galveston Bay, the Ship Channel and Clear Lake face open terrain — Exposure C, which lifts pressures over the suburban interior.
OPEN TERRAINWind-Borne Debris Fringe
Impact protection isn't blanket across the metro — it tracks the coastal debris region near the bay, so the debris line is a project-by-project call.
NEAR-COASTConfirm permitting and any local amendments through the City of Houston Development & Regulatory Affairs Department. Choosing Exposure C over B near the bay can raise design pressures sharply at the same wind speed, so the upwind-terrain call carries real cost.
THE RECORD THAT SET THE CODE
The storms that taught Houston to build for the wind, not just the water
Houston's design velocities are written in the damage ledger of hurricanes that reached the metro inland.
Harvey, 2017
Category 4 landfall near Rockport, then stalled four days over Houston — remembered for record rain, but its hurricane-force gusts damaged tens of thousands of structures across the metro.
CAT 4 · STALLED INLANDIke, 2008
Came ashore at Galveston as a Category 2, but a vast wind field carried hurricane gusts across all of Houston — 2.6 million residents lost power as the grid took wind damage inland.
CAT 2 · METRO-WIDE WINDAlicia, 1983
Drove a Category 3 directly through the Houston region, shattering high-rise glass downtown and showing how far inland wind-borne debris can travel across the plain.
CAT 3 · DOWNTOWNASCE 7-22 TABLE 1.5-1 · MAP SELECTION
Higher stakes pull from a longer-return-period map
Risk category doesn't multiply a load — it sends the design to a longer-return-period speed map, and over Harris County those maps climb.
| Risk Category | Houston Design Wind Speed | Representative Structures |
|---|---|---|
| Risk Category I | ~120–130 mph | Agricultural facilities, temporary structures, minor storage |
| Risk Category II | 130–140 mph | Homes, commercial, most standard occupancies |
| Risk Category III | ~140–150 mph | Schools, assembly >300, substantial hazardous materials |
| Risk Category IV | ~150–160 mph | Hospitals, fire stations, emergency shelters, EOCs |
PERMIT-READY IN HARRIS COUNTY
What a sealed Houston submission must carry
Calculations prepared by or under a Texas-licensed PE, built around the metro's inland velocity and suburban-to-open exposure.
Address-Resolved Velocity
Project address and zip with the ASCE 7-22 wind speed read at the site — typically 130–140 mph for Risk II.
Justified Exposure Call
Exposure B or C with documented upwind terrain — bay-side and Ship Channel sites trending toward C.
Risk Category Basis
Table 1.5-1 classification with supporting documentation, fixing which speed map the design reads from.
Full ASCE 7-22 Method
Complete velocity-pressure path — qz = 0.00256 Kz Kzt Kd Ke V² — documented end to end.
C&C and MWFRS Pressures
Component-and-cladding pressures for windows, doors, roof panels and walls, plus MWFRS where it applies.
Local-Amendment Check
City of Houston and Harris County amendments confirmed for the jurisdiction — flood-zone, foundation and wind provisions where they apply.
ACROSS THE TEXAS GULF COAST
Compare the coast and statewide rules
From the bay shore inland to the rest of Texas — how the wind maps shift city to city.
Galveston
Barrier-island Gulf city with the region's highest coastal velocity profile.
GULF ISLANDCorpus Christi
Coastal Bend bay city in the hurricane landfall corridor with TWIA territory.
COASTAL BENDSan Antonio
Inland Texas — lower wind map, no seacoast windstorm territory.
INLANDTexas Statewide
The full Texas wind-load picture and code-adoption schedule.
STATE HUBAll State Requirements
Every state's wind-load rules and ASCE 7 edition in one place.
NATIONALWind Speed by Location
Look up the design wind speed at any U.S. address.
SPEED MAPOFFICIAL HOUSTON + TEXAS SOURCES
Where the local authorities publish the rules
Primary references for permitting, county engineering and state PE licensing.
BUILT FOR THE GULF COASTAL PLAIN
Run Houston loads in minutes, not afternoons
Enter a Houston address or zip and the calculator pulls the ASCE 7-22 velocity, sets exposure for the site, applies risk category, and returns a PE-ready report for Texas permit submission.