The Category levels of hurricanes are determined by the Saffir-Simpson Wind Scale, from level 1 through 5, ith 5 being the most severe.
WHAT IS THE SAFFIR-SIMPSON WIND SCALE
To help reduce confusion about the impacts associated with the various hurricane categories as well as to provide a more scientifically defensible scale, the National Oceanic and Atmospheric Administration in 2010 introduced the Saffir-Simpson Hurricane Wind Scale. The scale divides hurricanes into five categories distinguished by the intensities of their sustained winds:
Very dangerous winds will produce some damage. Usually cause no significant structural damage to building structures; however, they can topple unanchored mobile homes, as well as uproot or snap trees.
Poorly attached roof shingles or tiles can blow off. Extensive damage to power lines and poles will likely result in power outages.
Extremely dangerous winds will cause extensive damage. Storms are strong enough to lift a house and inflict damage upon poorly constructed doors and windows. Mobile homes, whether anchored or not, are typically damaged, and many manufactured homes also suffer structural damage. Near-total power loss is expected with outages.
Devastating damage will occur. These storms can cause structural damage to small residences and utility buildings, particularly those of wood frame or manufactured materials. Buildings that lack a solid foundation, such as mobile homes, are usually destroyed. Electricity could be unavailable for several days to a few weeks after the storm passes.
Catastrophic damage will occur. Complete roof structural failure on small residences. Mobile and manufactured homes are leveled. These storms cause extensive beach erosion, while terrain may be flooded far inland. Most trees will be snapped or uprooted and power poles downed. Electricity could be unavailable for several days to a few weeks after the storm passes.
Catastrophic damage will occur. These storms cause complete roof failure on residences and industrial buildings. Very heavy and
irreparable damage to wood frame structures and total destruction to mobile/manufactured homes is prevalent. Massive evacuation of residential areas may be required if the hurricane threatens populated areas. Power outages will last for weeks to possibly months.