Hurricane Dangers: Winds

The intensity of a hurricane making landfall, or coming ashore, is measured by categories that indicate wind speeds and potential damage.

Tropical cyclones with maximum sustained surface winds of less than 39 miles per hour (mph) are called tropical depressions. Those with maximum sustained winds of 39 mph or higher are called tropical storms.

When a storm’s maximum sustained winds reach 74 mph, it is called a hurricane. The Saffir-Simpson Hurricane Wind Scale is a 1 to 5 rating, or category, based on a hurricane’s maximum sustained winds. The higher the category, the greater the hurricane’s potential for property damage.

Hurricanes reaching Category 3 and higher are considered major hurricanes because of their potential for significant loss of life and damage. Category 1 and 2 storms are still dangerous, however, and require people in the projected path to take precautions.

Even tropical storm-force winds are dangerous to those caught in them. For this reason, emergency managers plan on having their evacuations complete and their personnel sheltered before the onset of tropical storm 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 to people’s every day lives. And the strongest winds usually occur on the right side of the eye wall of the hurricane.

Wind speeds usually decrease significantly within 12 hours after a hurricane makes 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 wind gusts to nearly 100 mph.

Tornadoes

Hurricanes can also produce tornadoes that add to the storm’s destructive power. Tornadoes are most likely to occur in the right-front quadrant of the hurricane. However, they are also often found elsewhere embedded in the rain bands, well away from the center of the hurricane.

Hurricane Sally that struck Alabama in September 2020 spawned 19 tornadoes (Link).

Some hurricanes seem to produce no tornadoes, while others develop multiple ones. Studies have shown that more than half of the hurricanes making it to shore produce at least one tornado; Hurricane Buelah (1967) spawned 141 according to one study. In general, tornadoes associated with hurricanes are less intense than those that occur in other storms. Nonetheless, the effects of tornadoes, added to the larger area of hurricane-force winds, can produce substantial damage.

The National Weather Service does not have an accurate way to predict exactly which storms will spawn tornadoes or where they will touch down. The new Doppler radar systems have greatly improved the forecaster’s warning capability, but the technology usually provides lead times from only a few minutes up to about 30 minutes. Because of that, being prepared and having a plan is critical.

Copyright 2021 WTVY. All rights reserved.

Background Picture: Sam Speights walks with his dogs as he checks on the damage to his home in the wake of Hurricane Harvey, Sunday, Aug. 27, 2017, in Rockport, Texas. Speights tried to stay in his home during the storm but had to move to other shelter after his lost his roof and back wall. (AP Photo/Eric Gay)