Here in the Tennessee Valley, our main weather concern is and always will be tornadoes. It is what impacts us directly and can be the most deadly. Based on our geographical location at 375 miles inland from the Gulf Coast, hurricanes do not pose a direct threat to the Valley. However, they do pose as an indirect threat, which can be just as harrowing this far inland. Hurricanes are considered to be a larger synoptic scale system and many people think that winds are the primary concern with these sea monsters. However, this is a wrong assumption. While high winds are a concern, they are not considered to be the most dangerous element of a hurricane. According to the National Hurricane Center, the most dangerous elements of a hurricane, in order, are: flash flooding, storm surge, high winds and tornadoes. One of the biggest myths is that only those that live along the coast should be concerned when hurricanes are barreling toward the lower 48. While it is true that storm surges along the coast have the most potential for causing damage and deaths, in the last 15 years more people have been killed as a result of flash flooding as hurricanes move inland.
What happens when a hurricane moves inland?
When a hurricane moves inland, massive power outages can occur due to high winds and flash floods. An example is Hurricane Ivan that quickly moved through western North Carolina in September 2004. Thousands of people lost power, mainly due to flash flooding. As the flooding happened, many power poles fell because the land was too weak to hold them. Many trees were also uprooted due to high winds that came with Hurricane Ivan. Another issue when hurricanes move inland is the likelihood for spin-up tornadoes due to excessive wind shear. What does this mean exactly? As hurricanes move inland, the wind near the surface slows down while the wind aloft maintains their momentum, causing the wind to veer (or turn) with height. This is what can spawn a “spin-up” tornado. It is important to keep your eyes and ears tuned in to your local weather at all times, regardless of the type of weather. This is the only way to keep yourself informed and aware. As the saying goes, “knowledge is power.” The more you know, the better prepared you will be to protect your life and family in the event when severe weather strikes your community.
Warning or watch?
During a HURRICANE WARNING, hurricane conditions are expected in the warned area within 36 hours. These conditions include but aren’t limited to winds of at least 74 mph, dangerous storm surge and torrential rain. A hurricane warning can remain in effect at the coast when dangerously high water and exceptionally high waves continue even though winds are less than hurricane force. During a warning, complete storm preparations and immediately leave the threatened area if directed by local officials.
During a HURRICANE WATCH, hurricane conditions are possible in the mentioned area within 48 hours. Prepare your home and review your plan for evacuation in case a hurricane or tropical storm warning is issued. It is vital to listen closely to instructions from local officials. Both the hurricane path and intensity can change quickly.
A hurricane glossary
A HURRICANE is a tropical cyclone with winds of at least 74 mph. The term is applied to such storms in the Atlantic Basin and Pacific Ocean east of the International Date Line.
The EYE is the low-pressure center of a hurricane. Winds are normally calm and sometimes the sky is clear.
The EYE WALL is the ring of thunderstorms that surround the eye of a hurricane. The heaviest rain, strongest winds and worst turbulence are normally found here.
A STORM SURGE is an abnormal rise of water generated by a storm, over and above the predicted astronomical tides This rise in water level can cause extreme flooding in coastal areas, especially when storm surge coincides with normal high tide.
A TROPICAL DEPRESSION is a relatively weak tropical entity that has evidence of a closed center of circulation. Depressions have sustained winds of 23 to 38 mph.
TROPICAL STORM systems are named once they reach tropical storm strength with maximum sustained winds of 39 to 73 mph.
A TROPICAL WAVE is a kink or bend in the normally straight flow of surface air in the tropics that forms a low-pressure trough. These create showers and thunderstorms that can organize to develop tropical depressions, storms or hurricanes.
Saffir-Simpson Hurricane Wind Scale
The Saffir-Simpson Hurricane Wind Scale is a 1 to 5 rating based on a hurricane’s sustained wind speed. This scale estimates potential 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 preventative measures.
|1||74-95||Very dangerous winds will produce some damage: Well-constructed frame homes could have damage to roof, shingles, vinyl siding and gutters. Large branches of trees will snap and shallowly rooted trees may be toppled. Extensive damage to power lines and poles likely will result in power outages that could last a few to several days.|
|2||96-110||Extremely dangerous winds will cause extensive damage: Well-constructed frame homes could sustain major roof and siding damage. Many shallowly rooted trees will be snapped or uprooted and block numerous roads. Near-total power loss is expected with outages that could last from several days to weeks.|
|3||111-129||Devastating damage will occur: Well-built framed homes may incur major damage or removal of roof decking and gable ends. Many trees will be snapped or uprooted, blocking numerous roads. Electricity and water will be unavailable for several days to weeks after the storm passes.|
|4||130-156||Catastrophic damage will occur: Well-built framed homes can sustain severe damage with loss of most of the roof structure and/or some exterior walls. Most trees will be snapped or uprooted and power poles downed. Fallen trees and power poles will isolate residential areas. Power outages will last weeks to possibly months. Most of the area will be uninhabitable for weeks or months.|
|5||157+||Catastrophic damage will occur: A high percentage of framed homes will be destroyed, with total roof failure and wall collapse. Fallen trees and power poles will isolate residential areas. Power outages will last for weeks to possibly months. Most of the area will be uninhabitable for weeks or months.|