The intensity of a landfalling hurricane is expressed in terms of categories that relate wind speeds and potential damage. According to the Saffir-Simpson Hurricane Scale, a Category 1 hurricane has lighter winds compared to storms in higher categories. A Category 4 hurricane would have winds between 131 and 155 mph and, on the average, would usually be expected to cause 100 times the damage of the Category 1 storm. Depending on circumstances, less intense storms may still be strong enough to produce damage, particularly in areas that have not prepared in advance. For this reason, emergency managers plan on having their evacuations completed and their personnel sheltered before the onset of tropical storm-force winds, not hurricane-force winds.
Hurricane-force winds can easily destroy poorly constructed buildings and mobile homes. Debris such as signs, roofing material, and small items left outside become flying missiles in hurricanes. Extensive damage to trees, towers, water and underground utility lines (from uprooted trees), and fallen poles cause considerable disruption.
High-rise buildings are also vulnerable to hurricane-force winds, particularly at the higher levels since wind speed tends to increase with height. Recent research suggests you should stay below the tenth floor, but still above any floors at risk for flooding. It is not uncommon for high-rise buildings to suffer a great deal of damage due to windows being blown out. Consequently, the areas around these buildings can be very dangerous.
The strongest winds usually occur in the right side of the eyewall of the hurricane. Wind speed usually decreases significantly within 12 hours after landfall. Nonetheless, winds can stay above hurricane strength well inland. Hurricane Hugo (1989), for example, battered Charlotte, North Carolina (which is 175 miles inland) with gusts to nearly 100 mph.
High-Wind Safety Actions
Take these actions before hurricane season:
- Find out if your home meets current building code requirements for high winds. Experts agree that structures built to meet or exceed current building code high-wind provisions have a much better chance of surviving violent windstorms.
- Protect all windows by installing commercial shutters or preparing 5/8 inch plywood panels.
- Garage doors are frequently the first feature in a home to fail. Reinforce all garage doors so that they are able to withstand high winds.
- If you do not live in an evacuation zone or a mobile home, designate an interior room with no windows or external doors as a "Safe Room".
- Before hurricane season, assess your property to ensure that landscaping and trees do not become a wind hazard.
- Trim dead wood and weak / overhanging branches from all trees.
- Certain trees and bushes are vulnerable to high winds, and any dead tree near a home is a hazard.
- Consider landscaping materials other than gravel/rock.
Take these actions as a hurricane approaches:
- No mobile / manufactured home is safe in hurricane-force winds. Those residents should evacuate to a safer structure once local officials issue a hurricane evacuation order for their community.
- Once a hurricane warning is issued, install your window shutters or plywood panels.
- When a hurricane warning is issued for your community, secure or bring inside all lawn furniture and other outside objects that could become a projectile in high winds.
- Listen carefully for safety instructions from local officials, and go to your designated "Safe Room" when directed to do so.
- Monitor NOAA Weather Radio.
- Do not leave your "Safe Room" until directed to do so by local officials, even if it appears that the winds have calmed. Remember that there is little to no wind in the eye of a hurricane.