"weak" tornadoes, EF2 and EF3 are classified as "strong" tornadoes, with winds of at least major hurricane force, where EF4 and EF5 are categorized as "violent" tornadoes, with winds corresponding to category 5 hurricane winds and rising to match or exceed the strongest tropical cyclones on record. The EF scale is based on tornado damage (primarily to buildings), which makes it difficult to rate tornadoes that strike in sparsely populated areas, where few man-made structures are found. The Enhanced Fujita scale went into effect on February 1, 2007. Saffir–Simpson hurricane category scale The Saffir–Simpson hurricane wind scale, assigns a numerical classification of hurricanes into five categories distinguished by the intensities of their sustained winds. The scale spans from Category 1 (winds of at least ) to Category 5 (exceeding ). Unlike the Enhanced Fujita Scale, which assigns ratings for tornadoes after damage has been incurred and thoroughly assessed, categories on the Saffir-Simpson scale are assigned to most active cyclones that reach the minimum hurricane threshold, even before landfall. {| class="wikitable" style="text-align: right;" |- ! Category !! Sustained winds !! Storm surge !! Central pressure !! Potential damage !! style="width: 9em;"|Example(s) |- ! style="background: #;" | | 33–42 m/s 74–95 mph 64–82 knot 119–153 km/h | 4–5 ft 1.2–1.5 m | 28.94 inHg 980 mbar | style="text-align: left;" | No real damage to building structures. Damage primarily to unanchored mobile homes, shrubbery, and trees. Also, some coastal flooding and minor pier damage. | Jerry (1989) Ismael (1995) Danny (1997) Gaston (2004) Kate (2015) |- ! style="background: #;" | | 43–49 m/s 96–110 mph 83–95 kn 154–177 km/h | 6–8 ft 1.8–2.4 m | 28.50–28.91 inHg 965–979 mbar | style="text-align: left;" | Some roofing material, door, and window damage. Considerable damage to vegetation, mobile homes, etc. Flooding damages piers and small craft in unprotected anchorages may break their moorings. | Carol (1954) Diana (1990) Erin (1995) Marty (2003) Juan (2003) |- ! style="background: #;" | | 50–58 m/s 111–129 mph 96–113 kn 178–209 km/h | 9–12 ft 2.7–3.7 m | 27.91–28.47 inHg 945–964 mbar | style="text-align: left;" | 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. | Alma (1966) Alicia (1983) Roxanne (1995) Fran (1996) Isidore (2002) Sandy (2012) |-