Wind Scales

 

Saffir-Simpson Hurricane Scale
Category	Wind Strength - Pressure	Effects
1	65 to 83 knots 74 to 95 mph 119 to 153 kph > 980 mb	Storm surge generally 4-5 ft above normal. No real damage to building structures. Damage primarily to unanchored mobile homes, shrubbery, and trees. Some damage to poorly constructed signs. Also, some coastal road flooding and minor pier damage. Hurricanes Allison of 1995 and Danny of 1997 were Category One hurricanes at peak intensity.
2	84 to 95 knots 96 to 110 mph 154 to 177 kph 980 - 965 mb	Storm surge generally 6-8 feet above normal. Some roofing material, door, and window damage of buildings. Considerable damage to shrubbery and trees with some trees blown down. Considerable damage to mobile homes, poorly constructed signs, and piers. Coastal and low-lying escape routes flood 2-4 hours before arrival of the hurricane center. Small craft in unprotected anchorages break moorings. Hurricane Bertha of 1996 was a Category Two hurricane when it hit the North Carolina coast, while Hurricane Marilyn of 1995 was a Category Two Hurricane when it passed through the Virgin Islands.
3	96 to 113 knots 111 to 130 mph 178 to 209 kph 964 - 945 mb	Storm surge generally 9-12 ft above normal. Some structural damage to small residences and utility buildings with a minor amount of curtainwall failures. Damage to shrubbery and trees with foliage blown off trees and large tress blown down. Mobile homes and poorly constructed signs are destroyed. Low-lying escape routes are cut by rising water 3-5 hours before arrival of the hurricane center. Flooding near the coast destroys smaller structures with larger structures damaged by battering of floating debris. Terrain continuously lower than 5 ft above mean sea level may be flooded inland 8 miles (13 km) or more. Evacuation of low-lying residences with several blocks of the shoreline may be required. Hurricanes Roxanne of 1995 and Fran of 1996 were Category Three hurricanes at landfall on the Yucatan Peninsula of Mexico and in North Carolina, respectively.
4	114 to 134 knots 131 to 155 mph 210 to 249 kph 944- 920 mb	Storm surge generally 13-18 ft above normal. More extensive curtainwall failures with some complete roof structure failures on small residences. Shrubs, trees, and all signs are blown down. Complete destruction of mobile homes. Extensive damage to doors and windows. Low-lying escape routes may be cut by rising water 3-5 hours before arrival of the hurricane center. Major damage to lower floors of structures near the shore. Terrain lower than 10 ft above sea level may be flooded requiring massive evacuation of residential areas as far inland as 6 miles (10 km). Hurricane Luis of 1995 was a Category Four hurricane while moving over the Leeward Islands. Hurricanes Felix and Opal of 1995 also reached Category Four status at peak intensity.
5	135+ knots 155+ mph 249+ kph < 920 mb	Storm surge generally greater than 18 ft above normal. Complete roof failure on many residences and industrial buildings. Some complete building failures with small utility buildings blown over or away. All shrubs, trees, and signs blown down. Complete destruction of mobile homes. Severe and extensive window and door damage. Low-lying escape routes are cut by rising water 3-5 hours before arrival of the hurricane center. Major damage to lower floors of all structures located less than 15 ft above sea level and within 500 yards of the shoreline. Massive evacuation of residential areas on low ground within 5-10 miles (8-16 km) of the shoreline may be required. There were no Category Five hurricanes in 1995, 1996, or 1997. Hurricane Gilbert of 1988 was a Category Five hurricane at peak intensity and is the strongest Atlantic tropical cyclone of record.

The effects described in the Saffir-Simpson scale are from the National Hurricane Center

 

Dvorak Current Intensity Chart
The Dvorak technique is a method using enhanced Infrared and/or visible satellite imagery to quantitatively estimate the intensity of a tropical system. CI -- Current Intensity MWS -- Mean Wind Speed MSLP -- Mean Sea Level Atmospheric Pressure in Millibars
CI Number	MWS (Knots)	MSLP (Atlantic)	MSLP (Pacific)	Saffir-Simpson Category (Approximate)
1	25 Knots
1.5	25 Knots
2	30 Knots	1009 mb	1000 mb
2.5	35 Knots	1005 mb	997 mb
3	45 Knots	1000 mb	991 mb
3.5	55 Knots	994 mb	984 mb
4	65 Knots	987 mb	976 mb	1 (64-83 KTS)
4.5	77 Knots	979 mb	966 mb	1 (64-83 KTS); 2 (84-96 KTS)
5	90 Knots	970 mb	954 mb	2 (84-96 KTS); 3 (97-113 KTS)
5.5	102 Knots	960 mb	941 mb	3 (97-113 KTS)
6	115 Knots	948 mb	927 mb	4 (114-135 KTS)
6.5	127 Knots	935 mb	914 mb	4 (114-135 KTS)
7	140 Knots	921 mb	898 mb	5 (136+ KTS)
7.5	155 Knots	906 mb	879 mb	5 (136+ KTS)
8	170 Knots	890 mb	858 mb	5 (136+ KTS)