You’re probably watching Helene today, hopefully from a safe and dry location. We’re no strangers to hurricanes and tropical storms here in Mississippi, but it’s always good to refresh our memories on what all this stuff means!
The hurricane category system in the United States, known as the Saffir-Simpson Hurricane Wind Scale, classifies hurricanes based on their sustained wind speeds. This scale ranges from Category 1 to Category 5, with each category indicating the potential for damage.
Saffir-Simpson Hurricane Wind Scale:
Category 1: Wind speeds of 74-95 mph; some damage to structures and trees, with flooding risks in coastal areas.
Category 2: Wind speeds of 96-110 mph; significant damage to homes and trees, leading to potential power outages.
Category 3: Wind speeds of 111-129 mph; devastating damage, with many homes destroyed and severe flooding risks.
Category 4: Wind speeds of 130-156 mph; catastrophic damage, with most trees downed and extreme flooding.
Category 5: Wind speeds of 157 mph or higher; total destruction of homes, with complete roof failure and uninhabitable areas for weeks or months.
A tropical storm is characterized by sustained winds ranging from 39-73 mph, which can produce heavy rainfall and localized flooding. In contrast, a hurricane has sustained winds of 74 mph or higher, indicating a more intense system capable of causing significant destruction.
Tropical storms and hurricanes typically develop over warm ocean waters (at least 80°F) under specific conditions:
Warm water to fuel the storm’s energy; Moist air; Low wind shear, which allows the storm to strengthen vertically; and what’s known as the Coriolis Effect, caused by the earth’s rotation. When these conditions align, thunderstorms can organize and strengthen, evolving from a tropical depression to a tropical storm, and eventually to a hurricane.
The National Hurricane Center issues several alerts to inform the public:
Hurricane Watch: Issued when hurricane conditions are possible within 48 hours. Residents should prepare for potential evacuation and stock up on supplies.
Hurricane Warning: Issued when hurricane conditions are expected within 36 hours. Immediate action is advised for safety.
Tropical Storm Watch: Indicates that tropical storm conditions are possible within 48 hours.
Tropical Storm Warning: Signals that tropical storm conditions are expected within 36 hours.
Hurricane Helene reached the Gulf Coast late Thursday as an “extremely dangerous Category 4 hurricane,” forcing mandatory evacuations for several counties as its deadly storm surge reached up to 20 feet, triggering millions of power outages in the southeast. By this morning it has weakened to a tropical storm, but is causing flooding and power outages through Georgia and into the Carolinas.
Our hearts are with all those affected by this storm!
