The remnants of Hurricane Helene were not the only factor that contributed to the severity of the flooding that struck the mountain community of Asheville, North Carolina.

Several conditions in the region, including a precursor rain event and the topography of the land, gave rise to deadly flash flooding, experts told ABC News.

Hurricane Helene barreled into Florida’s Big Bend on Sept. 26 as a Category 4 hurricane, bringing 140 mph winds and a 15-foot storm surge to parts of the Gulf Coast. The hurricane exemplified the far-reaching impacts that a storm can have not only along the coast, but hundreds of miles inland. Following landfall, Helene tracked north, causing reported tornadoes in five states and dumping over 30 inches of rain in parts of North Carolina over the span of a few days.

Help people affected by Hurricane Helene. Your donation enables the Red Cross to prepare for, respond to and help people recover from this disaster. Donate now at redcross.org/abc.

When large hurricanes form in the Gulf, they tend to cause a precursor rain event farther inland as the system’s large rain shield – defined by the National Weather Service as “a solid or nearly solid area of rain that typically becomes heavier as one approaches the eye” – interacts with a cold front, Art DeGaetano, director of the NOAA Northeast Regional Climate Center at Cornell University, told ABC News.

The Asheville region had already received a deluge of rain in the days leading up to Helene, with more than a foot of rainfall in some spots, according to the North Carolina State Climate Office. As a result, the soil was saturated and rivers and streams filled to the brim by the time Helene, “the real whammy,” passed over the area, DeGaetano said. Once the French Broad River, which flows through Asheville, and its subsidiaries overflowed, the water rushed into nearby neighborhoods within minutes.

SEE ALSO: Hurricane Helene’s victims include first responders who died helping others

While the phenomenon does not happen often, it has happened before in the region, DeGaetano said. A similar event occurred in Asheville in what is known as the “Great Flood of 1916,” in which 80 people died.

In addition, the sheer size of the storm system allowed areas to get hit with rain earlier and longer, Marshall Shepherd, director of the Atmospheric Sciences Program at the University of Georgia and former president of the American Meteorological Society, told ABC News.

The mountainous topography of the region also played a major role in the flooding, Yuh-Lang Lin, a professor of atmospheric science at North Carolina Agricultural and Technical State University, told ABC News.

Orographic lifting, a process that occurs when hills or mountains force air to rise and cool, caused water vapor to condense and additional precipitation to form as it combined with Helene’s tropical system, Lin said.

That heavy moisture was then “squeezed” out of the atmosphere and dumped over the Asheville region in a short amount of time, DeGaetano said. In hilly and mountainous terrains, rainfall typically is funneled into valleys, rivers and streams, DeGaetano said.

“That’s where we see this extreme flooding in those types of places,” Jennifer Francis, an atmospheric scientist at the Woodwell Climate Research Center, told ABC News.

SEE ALSO: Grandparents found hugging after fallen tree kills them during Helene

Climate change also likely played a major role in the storm behavior displayed by Helene, DeGaetano said. The warm waters in the Gulf of Mexico helped the storm absorb even more moisture and intensify as it neared the coast, he said. The increased water vapor storage fueled the heavy precipitation experienced along Helene’s track.

Researchers are looking into whether an atmospheric river also contributed to the heavy precipitation, Shepherd said.

“You sort of had this multiple-whammy of the hurricane, that orographic lifting from the mountains and this atmospheric river,” he said. “Trillions of gallons of moisture coming in from the tropics.”

Human-amplified climate change is causing extreme rainfall events to become more frequent and more intense, according to the federal government’s Fifth National Climate Assessment, released in November, 2023.

Rising global temperatures are supercharging the water cycle and bringing heavier rainfall – and related flood risks – across the U.S. More intense extreme rainfall events increase the frequency and scale of flash flooding, in part because the influx of water is more than the current infrastructure was built to handle.

Most places on the East Coast have experienced an overall increase in rainfall due to climate change, DeGaetano said. In the Southeast, extreme precipitation events have increased by about 37% in recent decades, according to the National Climate Assessment.

HOUSTON, Texas (KTRK) — The dry heat continues through Thursday but moisture starts streaming back in Friday into the weekend which could aid in some slim rain chances for SE Texas.

We started off Thursday with temperatures in the upper 60s but under sunny skies, we’ll see temps top out in the low to mid 90s. We also will have an ozone pollution watch in effect.

How long will the dry air stick around?

The lower humidity should hang around until Friday as we get grazed by tropical moisture rotating around a disturbance in the Gulf of Mexico.

It seems like it’s been pretty warm and dry lately. Any concern for drought conditions?

The amount of rain most of Southeast Texas has seen over the past two to three weeks has been minimal, though some areas seeing more than others. Still, much of the region now shows up on the regional drought monitor with abnormally dry conditions for this time of year. Houston has only seen about a quarter of an inch of rain over the past two weeks. So while it’s not an immediate concern, drought conditions will creep back in if we don’t get our normal October rains from fall fronts.

When is our next cool front coming?

At this time we have one penciled in for next Monday. This front looks to pass through mostly dry, and it should deliver a more noticeable temperature drop with highs in the 80 and lows in the 60s.

What are you tracking in the tropics?

We’re monitoring an area in the Gulf that has a low chance of development. Meanwhile, the deep tropics and Atlantic are very active right now with storms spinning in the middle of the ocean. Head to our daily Tropical Update page for the latest on what’s happening in the tropics.

The confirmed death toll for Hurricane Helene rose to at least 200 people as of Wednesday evening, The Associated Press reported, making it the deadliest hurricane since Katrina to hit the mainland U.S.

The death toll was at 189 Thursday morning but eight new deaths reported in Georgia and three from North Carolina upped that number to 200 by noon.

Search and rescue operations continued Thursday in the mountains of western North Carolina, which bore the worst of the storm.

The storm surge, wind damage and inland flooding from Hurricane Helene have been catastrophic, flooding neighborhoods, stranding residents and destroying homes in Florida, Georgia, South Carolina, North Carolina, Virginia and Tennessee.

RELATED: How to help those impacted by Hurricane Helene: Charities, organizations to support relief efforts

As recovery efforts continued across the Southeast, President Joe Biden and Vice President Kamala Harris traveled to the region Wednesday to survey the destruction while rescuers keep searching for the missing.

“I’m here to say the United States — the nation — has your back,” Biden told a crowd in Raleigh, North Carolina. “We’re not leaving till you’re back on your feet completely.”

Helene, which made landfall in Florida’s Big Bend region Thursday night as a massive Category 4 hurricane, was the strongest hurricane to make landfall in the Big Bend on record.

1.2 million customers still without power in some southern states

As recovery efforts from Hurricane Helene’s catastrophic force continue, 1.2 million customers are still without power in some southern states.

As of Wednesday at 12:30 p.m., 1,276,750 customers are without power across the South, according to poweroutage.us.

RELATED: Mayorkas warns FEMA doesn’t have enough funding to last through hurricane season

The hardest-hit states are South Carolina with over 484,410 customers without power, North Carolina with over 343,632 customers without power and Georgia with over 354,418 customers without power.

Outages are also reported in Florida (40,724 customers), Virginia (40,184 customers) and West Virginia (13,382 customers).

Biden deploying up to 1,000 active-duty troops to support NC National Guard

President Joe Biden announced Wednesday he has directed the deployment of “up to one thousand active-duty soldiers to reinforce the North Carolina National Guard.” The announcement comes as Biden will travel to South Carolina and North Carolina Wednesday to survey the impacts of Hurricane Helene.

“These soldiers will speed up the delivery of life-saving supplies of food, water, and medicine to isolated communities in North Carolina — they have the manpower and logistical capabilities to get this vital job done, and fast. They will join hundreds of North Carolina National Guard members deployed under State authorities in support of the response,” Biden said in the statement.

ALSO SEE: Hurricane Kirk strengthens into Category 3 storm in the Atlantic but not yet deemed a threat to land

“Hurricane Helene has been a storm of historic proportion. My heart goes out to everyone who has experienced unthinkable loss. We are here for you — and we will stay here for as long as it takes,” Biden added.

The White House fact sheet says the soldiers will “support the delivery of food, water, and other critical commodities,” to impacted communities. The fact sheet adds the deployment is effective immediately. The soldiers are part of the Infantry Battalion Task Force based in Fort Liberty, North Carolina, and includes a Forward Support Company, according to the administration.

Bipartisan senators call on Congress to address Hurricane Helene damage

In a joint letter released Tuesday, Senate leaders Chuck Schumer, Mitch McConnell and several other senators on both sides of the political aisle called on Congress to meet following the devastation of Hurricane Helene.

“Although the true level of devastation is still unfolding, it is clear that Congress must act to meet the unmet needs in our states and address the scope and scale of destruction experienced by our constituents,” the leaders wrote in the letter.

The senators suggested Congress convene in October to “ensure we have enough time to enact legislation before the end of this calendar year.”

RELATED: Hurricane Helene’s victims include first responders who died helping others

“Tens of millions of Americans were impacted by Hurricane Helene, and we look forward to working with you to provide relief to those impacted by this horrific storm,” the senators wrote.

Help people affected by Hurricane Helene. Your donation enables the Red Cross to prepare for, respond to and help people recover from this disaster. Donate now at redcross.org/abc.