As Florida’s Gulf Coast braces for the imminent impact of Hurricane Helene, projected to hit land on Thursday evening, meteorologists are cautioning that the storm’s powerful rain and winds could lead to significant flooding even many miles from the shore.

According to the National Oceanic and Atmospheric Administration, Helene’s winds reach as far as 275 miles from its center, classifying it as an extraordinarily large storm capable of causing flooding far inland, even after it makes landfall. Anticipated heavy rainfall will commence in various southeastern states prior to the storm’s arrival.

By Friday, regions in the southern Appalachian area could see rainfall accumulation of up to 18 inches. Enhanced urban flooding risks are present in cities like Tallahassee, the metro Atlanta area, and western North Carolina.

“Extreme rainfall rates, particularly in the hilly areas of the southern Appalachians, are expected to lead to flash floods, landslides, and notably severe flooding of rivers and streams,” NOAA stated in an unusual warning specifically addressing the risk of inland flooding.

Flooding has been the leading cause of fatalities associated with hurricanes and tropical storms in the United States over the past decade.

Destructive Winds and Flooding Will Reach Well Past Florida

Although the severe risk of flooding is primarily forecasted for the Appalachians, a lesser degree of flooding risk extends as far north as southern Indiana, Ohio, and the Washington, D.C. metropolitan area, as reported by the National Weather Service.

AccuWeather’s Chief Meteorologist Jonathan Porter warned, “Helene has the potential to cause a flooding catastrophe in several areas of the southeastern U.S., particularly in northern Georgia, upstate South Carolina, and western North Carolina.”

The flooding will be exacerbated by both the rain arriving before Helene’s landfall and the heavy downpours expected as the storm progresses inland. Recent flash flooding from unrelated rain has already occurred in parts of northern Georgia, upstate South Carolina, western North Carolina, eastern Tennessee, southwestern Virginia, and southern West Virginia, affecting areas with 2 to 8 inches of rainfall from Tuesday until Wednesday night.

Governor Glenn Youngkin of Virginia has declared a state of emergency ahead of Helene, emphasizing that western areas of the state are likely to experience significant rainfall and flooding on Friday and Saturday.

In a positive note, the heavy rainfall spread over parts of Virginia, West Virginia, and Kentucky may help alleviate the ongoing drought conditions.

Factors Behind Excessive Rainfall Inland

Beyond the sheer size of Helene, another phenomenon could amplify the inland rains associated with this storm. This involves the Fujiwhara effect, which describes the interaction between two rotating storm systems.

Hurricane Helene may interact with another low-pressure system in the south-central U.S., resulting in heavy rain further from the storm’s center. According to forecasters, this could lead to extensive rainfall in regions like the Mid-South and Ohio Valley over the next few days.

This weather interaction resembles a dance between two storm systems rotating around a mutual center, a scenario that can occur when they are approximately 900 miles apart.

Safety Precautions Against Severe Flooding

• Evacuate if local emergency services recommend it.
• Identify if your residence is in a flood-prone area.
• Formulate a plan to safeguard your family and belongings.
• Assemble an emergency kit that includes water, non-perishable food, medications, and essential supplies. Here’s what you should include.
• Avoid flooded roads; do not drive through floodwaters.