- Education and Science
Discover More about Hurricanes: Expected Damage Based on Hurricane Category
Hurricanes are classified into different categories based on the Saffir-Simpson Hurricane Scale. This method of classifying hurricanes was developed in the 1970’s to predict the type of damage that might be created from different levels of storms. The system was created by Herbert Saffir, a consulting engineer and Dr. Robert Simpson , former director of the national Hurricane Center. The classification system takes into account sustained wind speeds, storm surge, and barometric pressure. Below is a description of each type of hurricane category and the types of damage that might be seen with each.
Category 1 – Minimal damage
Maximum sustained wind speeds of 74-95 mph
Storm surge is 4-5 feet
Barometric pressure is greater than 980 mb or 28.94 in
Category 1 storms are the lowest level hurricane on the scale. But keep in mind that they are still hurricanes and that means they are more powerful than tropical storms. You typically would not see significant damage to most structures. Trees, shrubbery may show signs of impact as well as poorly constructed signs or unanchored mobile homes. Keep an eye out for coastal roads that may be flooded by the storm surge. Piers on the coast also may have minimal damage.
Category 2 – Moderate damage
Maximum sustained wind speeds of 96-110 mph
Storm surge is 6-8 feet
Barometric pressure is 965-979 mb or 28.50-28.91 in
Category 2 storms will blow down some trees, so look out for this on the roads. Tree foliage will be heavily damaged as well as shrubbery. Although there should be no major damage to most buildings, you may still see damage to windows, doors and roofs. Exposed mobile homes will suffer major damage and so will poorly constructed signs. If you live near the coast, be aware that coastal roads and low-lying escape routes will flood about two to four hours before the hurricane makes landfall. Due to the higher storm surge, marinas will flood which may affect small boats (torn from moorings). Piers will suffer considerable damage.
Category 3 – Extensive damage
Maximum sustained wind speeds of 111-130 mph
Storm surge is 9-12 feet
Barometric pressure is 945-964 mb or 27.91-28.47 in
If a Category 3 storm hits your area, don’t be surprised to find that large trees have been blown down. Leaves and branches may also be blown off. Mobile homes are most vulnerable and most are completely destroyed. On buildings, expect damage to roofs, windows, and doors and for smaller buildings, structural damage may be apparent. Be aware that low-lying escape routes can be cut off by the rising storm surge from 3-5 hours before landfall. Due to this and serious flooding concerns, homes that are within several blocks of the coastline may be evacuated. Flooding of those areas that are up to 5 feet above sea level may occur even up to 8 miles inland. Small structures along the coast are extremely vulnerable and may be destroyed. Larger structures can be affected by the strong waves and floating debris.
Category 4 – Extreme damage
Maximum sustained wind speeds of 131-155 mph
Storm surge is 13-18 feet
Barometric pressure is 920-944 mb or 27.17-27.88 in
Category 4 storms usually prompt widespread evacuations from along the coast and also inland residences up to 6 miles from the coastline. The storm surge will usually cause flooding of escape routes up to 5 hours before the storm makes landfall. The storm will also cause major erosion from beaches. The extreme winds will blow down all signs, shrubs and trees. Mobile homes have no chance in this type of storm and are totally demolished. Most other residences suffer major damage to roofs, windows and doors and some small residences can have major structural failure (roof). The lower floors of coastal residences are severely affected by waves and floating debris. Flooding of areas that are up to 10 feet above sea level occurs up to 6 miles inland
Category 5 – Catastrophic damage
Maximum sustained wind speeds over 155 mph
Storm surge is greater than 18 feet
Barometric pressure is less than 920 mb or 27.17 in
Category 5 represents the highest degree of hurricane and causes widespread destruction. Evacuations up to 10 miles inland are usually implemented. Escape routes can be flooded by the storm surge from 3-5 hours before the storm hits. Most residences are severely affected with damage to roofs, windows (shattered), and doors; mobile homes are completely destroyed. Structural damage such as roof failure is widely seen in both residences and commercial buildings. It is common to see whole buildings destroyed or blown away by the winds. Beware for fallen trees, shrubs and signs that have all been blown down onto roads. Any coastal structures within 1500 feet of the shoreline suffer severe damage to lower floors (up to 15 feet above sea level).
National Hurricane Center: http://www.nhc.noaa.gov/