The five categories are, in order of increasing intensity:
| Cat. | Sustained Winds | Storm Surge | Potential Damage |
|---|---|---|---|
| 1 | 74-95 mi/h 64-82 kt 119-153km/h |
4-5 ft 1.2-1.5m |
No real damage to building structures. Damage primarily to unanchored mobile homes, shrubbery, and trees. Also, some coastal flooding and minor pier damage. |
| 2 | 96-110 mi/h 83-95 kt. 154-177km/h |
6-8 ft. 1.8-2.4m |
Some roofing material, door, and window damage. Considerable damage to vegetation, mobile homes, etc. Flooding damages piers and small craft in unprotected moorings may break their moorings. |
| 3 | 111-130 mi/h 96-113 kt. 178-209km/h |
9-12 ft. 2.7-3.7m |
Some structural damage to small residences and utility buildings, with a minor amount of curtainwall failures. Mobile homes are destroyed. Flooding near the coast destroys smaller structures with larger structures damaged by floating debris. Terrain may be flooded well inland. |
| 4 | 131-155 mi/h 114-135 kt. 210-249km/h |
13-18 ft. 4.0-5.5m |
More extensive curtainwall failures with some complete roof structure failure on small residences. Major erosion of beach areas. Terrain may be flooded well inland. |
| 5 | ≥156 mi/h ≥136 kt. ≥250km/h |
≥18 ft. ≥5.5m |
Complete roof failure on many residences and industrial buildings. Some complete building failures with small utility buildings blown over or away. Flooding causes major damage to lower floors of all structures near the shoreline. Massive evacuation of residential areas may be required. |