Devastating effects of Hurricane Helene predicted far beyond Florida

As Florida's Gulf Coast braces for devastating Hurricane Helene, which is set to make landfall Thursday night, meteorologists warn that heavy rains and winds will cause flooding even hundreds of miles inland.

Helene's winds reach as far as 275 miles from its center, making it a massive storm that could cause inland flooding long after it makes landfall, the National Oceanic and Atmospheric Administration said. Because of its size, the southeastern part of the country will experience heavy rains even before it makes landfall.

Rainfall amounts of up to 460 mm are expected as far south as the Appalachians by Friday. There is a risk of severe flooding in Tallahassee, the Atlanta metropolitan area and western North Carolina.

“Extreme amounts of precipitation (that is, torrential rain) in the mountainous terrain of the southern Appalachians are likely to inundate communities in their path with flash floods and landslides and cause extensive river and stream flooding,” NOAA said in a rare news release warning of the risk of inland flooding.

Flooding was the leading cause of death from hurricanes and tropical cyclones in the United States over the past decade.

Destructive winds and flooding will spread beyond the Florida coast

While the greatest flood risk is expected inland in the Appalachian Mountains, a low risk of flooding extends further north into southern parts of Indiana, Ohio and across to the Washington, DC metropolitan area, according to the National Weather Service

“Helene could cause a flooding disaster in some areas of the southeastern United States, particularly northern Georgia, northern South Carolina and western North Carolina,” said Jonathan Porter, AccuWeather chief meteorologist.

The flooding is being caused by a combination of rainfall before Helene makes landfall and the heavy rains expected as the storm moves over land. The region from northern Georgia into northern South Carolina, western North Carolina, eastern Tennessee, southwest Virginia and southwestern West Virginia already experienced sudden flooding Tuesday night from rainfall between 2 and 8 inches (5 and 20 centimeters) unrelated to Helene, AccuWeather reported.

Virginia Governor Glenn Youngkin declared a state of emergency in preparation for the impacts of Helene, warning that western parts of the state could see significant rainfall and flooding on Friday and Saturday.

One bright spot: Heavy rains extending into parts of Virginia, West Virginia and Kentucky could ease a persistent drought.

Why so much rainfall inland?

In addition to the sheer size of Helene, there is another factor that could amplify this storm's rainfall inland. It's the so-called Fujiwhara effect, where two storms orbit around each other.

Hurricane Helene may merge with another storm over the south-central U.S., a low-pressure system that could bring torrential rain with the risk of flooding in states far from the storm's center. The heavy, potentially flooding rain could hit the Mid-South and Ohio Valley in the next few days, forecasters said.

The effect is like a dance between two storm systems rotating in the same direction and moving around a midpoint between them. This can happen when they are about 900 miles apart. Read more about meteorology's most exquisite dance.

How to protect yourself from extreme flooding

Officials say even people hundreds of kilometers from the mainland should make a plan for their safety:

Evacuate if instructed to do so by local emergency authorities.
Pay attention to whether you live in an area at risk of flooding.
Have a plan to protect your family and property.
Prepare an emergency kit with water, nonperishable foods, medications and more. Here's what to pack.
Avoid flooded roads. Do not attempt to drive through water.

Contributor: Doyle Rice, USA TODAY

Destructive winds and flooding will spread beyond the Florida coast

Why so much rainfall inland?

How to protect yourself from extreme flooding

Leave a Reply Cancel reply