Hurricane Helene proved catastrophic for Appalachia, as the storm's massive rainfall caused rampant flooding that devastated several cities and killed dozens of people. On Monday, the North Carolina State Climate Office provided a picture of the “monster storm” being almost a “worst-case scenario for Western North Carolina.”

“Torrential rains from the remnants of Hurricane Helene ended three days of extreme, unrelenting rainfall that were easing catastrophic flooding and unimaginable damage in our mountains and southern foothills,” the office said in a post. “…it will take years to document the full extent of this event – let alone recover from it.”

Here's how the climatologists said it happened.

North Carolina was drenched in rain before Helene hit

By the time Helene became a Category 1 hurricane in the Gulf of Mexico – more than 500 miles and 30 hours from where it would eventually make landfall in Florida – it was already raining in western North Carolina. The climate bureau says the outskirts of Helene added tropical moisture to slow-moving storms that formed along a stalled cold front.

At midnight Thursday – about an hour after Helene landed 10 miles north of Steinhatchee, Florida – the plane arrived at Asheville Airport North Carolina had already seen more than 10 cm of rain. This downpour stopped before Helene's outer ligaments even advanced. On Thursday evening, Yancey County, which is south of Erwin, Tennessee, where flooding became so severe that people were trapped inside Roof of a hospitalhad seen more than 9 inches of rain.

The water was already beginning to flood cities “while the heaviest rain from Helene was just beginning to fall,” the climate agency said. The more than 300 miles of tropical storm-force winds that Helene generated only exacerbated the situation, driving even more moisture into the mountains.

“Due to its enormous size, the effects of the storm were particularly long-lasting. It developed in a high humidity environment over the warm Gulf of Mexico, allowing it to grow and intensify unhindered,” the office said. “…From the start of the first frontal showers Wednesday evening to the passage of the Heart of Helene Friday morning, it was one of the most incredible and impactful weather events our state has ever experienced.”

Record Rain Brings Reports of “Biblical Desolation”

The western mountains of North Carolina received more than 8 inches of rain from Wednesday through Friday, with up to 12 inches or more in some areas, the bureau said. The highest rainfall total was in Busick, with a three-day rainfall total of 31.33 inches – more than 2.5 feet.

At least a dozen weather stations recorded the wettest three-day periods on record, the bureau said. Asheville Regional Airport lost communications Friday morning after Helene landed, but had already reported nearly 14 inches of rain. That amount, the bureau said, was “nearly three months’ worth of rainfall…in less than three days.”

All this rain resulted in river flooding, landslides and mudslides and led to rescue operations in several counties.

In Buncombe County, home to Asheville, emergency services deputy director Ryan Cole told the Citizen-Times that “catastrophic devastation” doesn't accurately describe the flood's impact.

“It would go a little further and say we are seeing biblical devastation across the county,” Cole said. “We had a biblical flood here, and it was extremely significant.”

The newspaper quoted County Manager Avril Pinder as saying, “This appears to be Hurricane Katrina in Buncombe County.”

Rare mountain tornado as Helene's winds move in

“Helene brought the full range of hurricane impacts to North Carolina,” the climate bureau said, “in full force, just hours after making landfall at Category 4 strength.”

Helene's winds were felt across western North Carolina, with the Charlotte airport experiencing the strongest wind gusts since a thunderstorm microburst in August 2019. The winds, which exceeded hurricane speeds in some places, contributed to widespread power outages. Because of Helene, millions of people were without power in several states, and as of Tuesday morning, hundreds of thousands are without power in North Carolina alone.

On Wednesday evening, as the state battled existing storms ahead of Helene, a rare mountain tornado formed in Watauga County, the first since 1998. The day after Helene made landfall, at least six tornadoes were confirmed, including an EF3 in Rocky Mountain that damaged several buildings destroyed.

A historic and deadly storm

CBS News has confirmed that Helene killed at least 131 people in multiple states. At least 40 deaths were reported in Buncombe County alone, including a 7-year-old who was swept away by floodwaters along with his grandparents.

While hundreds of people were saved, there were even more applications for social assistance. And given the severity of the damage, the climate agency said, it is expected that “the death toll is likely to rise as access to hard-hit areas is finally achieved in the coming days.”

“Unfortunately, our state's long-standing benchmark for deaths during a tropical event – about 80 during the mountainous region's flood in July 1916 – may be at risk from this storm, which has already broken many other records,” the climate office said, adding The event of 1916 was the region's record flood for more than a century – a title that “now belongs to Helene instead.”

Several rivers exceeded their highest crests by several feet, including the Swannanoa River, which experienced “the worst flooding along the river since North Carolina became a state,” the bureau said.

As unprecedented as Helene's impact on the region has been, there is a chance it will not be the last.

“Helene's rapid intensification over the Gulf, the amount of moisture available in its surroundings, and its manifestation as locally heavy – and in some cases historically unprecedented – rainfall are all known side effects of a warmer atmosphere,” the office said.

Last year was already the warmest year ever recorded by humanity, and 2024 has seen countless heat records. Continued use of fossil fuels releases greenhouse gases that trap heat in the atmosphere and increase average temperatures, leading to extreme weather events like Helene.

It's unclear when an event like Helene would hit the Appalachian Mountains again, but the Climate Office is almost certain of one thing: “We won't see another Helene in the Atlantic.”

Officials often withdraw hurricane names when they are particularly devastating, and while such measures have not yet been announced, climatologists believe it may only be a matter of time.