Hurricane Helene aftermath: Flooding in Asheville, death toll, and more.

The scenes from North Carolina are shocking: roads and bridges washed away. Houses ripped from their foundations. Entire towns reduced to mud and debris.

On Thursday night, Hurricane Helene slammed Florida as a Category 4 storm with winds reaching 140 miles per hour. In coastal communities, Helene knocked down trees and power lines, and caused record storm surge.

Yet some of its most devastating impacts were farther inland as the storm moved across the Southeast. Even before the bulk of the storm arrived in North Carolina, Helene started dumping rain in southern Appalachia — and loads of it. Over the last several days some regions in western North Carolina, near Asheville, recorded more than 2.5 feet.

“We have biblical devastation through the county,” Ryan Cole, the assistant director of Buncombe County Emergency Services, said in a press briefing Saturday afternoon. “We’ve had biblical flooding here.”

So far more than 100 deaths are linked to Helene across six states, including Florida, Georgia, and North Carolina. That number is almost certain to rise. Hundreds of people are still unaccounted for, in part because millions of households have lost power and there are still widespread cell outages. Many roads are also inaccessible, making rescue operations challenging.

Stunned by the devastation, some residents have compared flooding in parts of North Carolina to the impacts from Hurricane Katrina, which made landfall in Louisiana in 2005. Katrina claimed more than 1,800 lives. In the weeks to come, Helene may become one of the deadliest US hurricanes in recent history.

The eighth named storm of the Atlantic hurricane season, Helene is yet another reminder that climate change — which can intensify hurricanes and flooding — costs human lives. Record-warm water in the Gulf of Mexico supercharged the storm and loaded it with moisture. Generally speaking, hot air also holds more water. Together these dynamics helped turn Helene into a deadly, super-wet storm.

And as these last few days have revealed, it’s not just coastal communities that are vulnerable. Asheville has been dubbed a climate haven — a refuge from the impacts of warming and its consequences. But in reality, few places are completely safe.

After developing in the Caribbean early last week, Helene rapidly intensified into a Category 4 storm, before slamming into the Big Bend region of Florida late on Thursday. That’s the area where the panhandle meets the peninsula.

Helene broke storm surge records along Florida’s Gulf Coast, inundating coastal cities and towns like Tampa Bay and Cedar Key with sand and seawater. Some areas saw water levels rise 15 feet above ground level, according to preliminary modeling by the National Hurricane Center. It left homes in ruins.

Much of the worst damage, however, was in regions far less familiar with the threat of tropical storms: the mountains of Georgia, Tennessee, and especially North Carolina. The main problem there was abundant, unceasing rain, which caused rivers to balloon in populated areas like Atlanta and Asheville, the largest city in western North Carolina.

Videos and images over the weekend showed much of Asheville’s River Arts District — which hugs the French Broad River, southwest of downtown — inundated with water. Many of the shops and businesses, which are a lifeblood of the region, are unsalvageable, Will Hofmann, of the Asheville Citizen Times, reports. (I recommend following the Times’ coverage for updates about Asheville.)

State officials said all roads in western North Carolina, including parts of Interstate 40, were closed and should only be used by emergency vehicles. In nearby Tennessee, meanwhile, more than a dozen bridges are closed and five of them “are completely gone,” the state’s Department of Transportation said Sunday.

Power outages and water shortages are also rampant across the Southeast. As of late Monday morning, more than 2 million people were without electricity across South Carolina, Georgia, North Carolina, Florida, and Virginia, according to PowerOutage.us. Parts of western North Carolina are under a boil water advisory, due to a disruption in the public water supply. Emergency workers will deliver bottled water in Asheville beginning Monday afternoon.

Stormwater is now starting to recede, though it will likely take months if not years for hard-hit regions like Asheville to rebuild.

Similarly, it will take weeks to get a full tally of all the damage, though initial estimates suggest it will be in the billions of dollars. CoreLogic, an analytics firm, put its initial tally between $3 billion and $5 billion in insured losses. Moody’s Analytics expects a toll from $20 billion to $34 billion. AccuWeather, meanwhile, is setting the price tag between $145 billion and $160 billion.

These are all coarse initial estimates, but they indicate the magnitude of the devastation. The higher projections would put Helene in the top tier of costliest storms in the US. Hurricane Katrina, currently the most expensive weather disaster in US history, extracted about $170 billion from the economy. Hurricane Harvey in 2017 cost about $125.

The dollar value, however, doesn’t tell the whole story. Damage estimates are typically based on insurance claims, but with rising premiums across the country, more homes and businesses are not seeking financial protection. The insured value of a property doesn’t directly translate into suffering, either. A multimillion-dollar coastal vacation home getting swept down a hillside will register as a higher loss on an insurance company’s balance sheet than a destroyed mobile home that’s the sole residence and store of wealth for a family.

The simplest reason is that Helene was huge, stretching more than more than 400 miles wide, so its impacts — the wind and rain — reached well beyond the eye. Most hurricanes are around 300 miles in diameter.

What’s more is that the storm crossed an exceptionally warm ocean before reaching the mainland. The evaporation of that warm ocean water, which sends columns of moisture into the atmosphere, is what fuels hurricanes, and loads them up with water.

Even before Helene made landfall in Florida, bands of moisture from the hurricane were pulled into Appalachia. Satellite imagery showed almost the entire East Coast shrouded in cloud cover. That means that some regions were already starting to flood even before the bulk of Helene arrived.

“Recent rainfall in these areas, especially the southern Appalachians, have left the grounds saturated and the river tributaries running high,” the National Oceanic and Atmospheric Administration (NOAA) warned last Wednesday. “Additional rainfall from Helene will exacerbate the existing flood risk.”

It’s also worth noting that this is a wet region of the country. The areas surrounding Asheville are temperate rainforests, full of streams and rivers that run alongside human communities.

Helene’s destruction underscores that the impacts of a storm are not simply a function of wind speed and rain totals. They’re also influenced by the amount of people and property in harm’s way and how ready they are to face a disaster head-on.

We know that Helene is already on course to join the ranks of the costliest storms in US history. What all those storms have in common is that they made landfall in the continental US at high intensities in populated areas: Harvey struck the Texas coast at Category 4 strength, Katrina rammed into Louisiana and Mississippi as a Category 3 storm, while Helene was a Category 4 when it hammered Florida’s Big Bend region.

But the hurricane category ranking system is mainly based on wind speed, while the most dangerous element of these storms is the sheer quantity of water in the form of rainfall and storm surge. All three of these storms caused extensive flooding.

Their destruction also compounded on top of local vulnerabilities. Houston suffered intense flooding after Harvey because of the inordinate amount of rain it received, but also because the city is densely populated, relatively flat, and close to sea level. Sections of New Orleans sit below sea level and when Katrina struck, the city’s flood control infrastructure catastrophically failed. Helene landed in Florida’s Big Bend region, which is still recovering from the last major hurricane, before moving further inland and dumping rain on regions that have much less experience and infrastructure to cope with extraordinary volumes of water.

A growing number of people are also living in areas most likely to get hammered by hurricanes, and these states are building more property and infrastructure to accommodate them. That means that when a storm does make landfall, it puts more people in danger and damages more homes, offices, roads, and power lines.

Before Helene made landfall, forecasters at NOAA put out a rare news release and blunt warning about the storm’s impending damage. The agency said that the hurricane would cause “catastrophic, life-threatening inland flooding.”

The governors of Alabama, Florida, Georgia, North Carolina, and South Carolina heeded these alerts and submitted emergency declaration requests to the White House. Evacuation orders were issued for parts of North Carolina, Tennessee, and Florida, but some residents didn’t obey them.

Disaster declarations allow the Federal Emergency Management Agency to get involved in the response with emergency shelters, medical aid, and grants for helping people recover. More than 1,270 rescuers were sent to the afflicted areas. States also mobilized National Guard units to assist with rescue and relief efforts. During a press conference on Monday, President Joe Biden said he may have to call Congress back into session to get more funding to help with the response. Both former President Donald Trump and Vice President Kamala Harris altered their presidential campaign schedules in response to the hurricane.

Trump criticized Biden for not being in Washington, DC, during the storm, but Biden said he’s been following the situation and will visit areas hit hard by the disaster once rescue operations wind down. Trump is also planning to visit Georgia to get an update on the storm.

Ad hoc networks of local volunteers have also sprung up to provide assistance and relief, even deploying private airplanes and helicopters to bring supplies to areas now isolated by floods and destroyed roads.

Though hurricanes are uncommon in many of the places where Helene tore through, a few have passed directly through inland regions like western North Carolina before.

Tracing out the specific role of climate change in Helene’s destruction will take some time, but there are now some established ways that rising temperatures amplify the harms from hurricanes. Hotter air and water make the strongest hurricanes stronger and fuel rapid intensification, where a storm’s winds pick up by 35 miles per hour or more in less than 24 hours.

Warmer air holds onto more moisture, which means that hurricanes dish out more rain. A hotter climate also makes the ice caps melt and causes the ocean itself to expand, lifting sea levels and expanding the reach of storm surges. Combined, these two factors create more flooding in the wake of a hurricane. Floods are often the deadliest and more destructive aspect of hurricanes.

Helene arose amid one of the hottest years on record, with ocean temperatures near record highs and atmospheric conditions suited for hurricane formation. NOAA anticipated that this year’s hurricane season would be above average.

And risks are mounting. According to the most recent National Climate Assessment, a US government report, the growing population in the region hit by Helene, particularly in cities, has created new vulnerabilities to warming. “Over the last few decades, economic growth in the Southeast has been concentrated in and around urban centers that depend on climate-sensitive infrastructure and regional connections to thrive,” according to the report.

To find out where people need the most help, local news outlets have some of the most up-to-date reports of the situation on the ground.

Blue Ridge Public Radio has compiled a list of ways to help victims in western North Carolina. The Knoxville News Sentinel has a similar list for eastern Tennessee. FEMA also has links to state volunteer groups assisting with the recovery.

Some state emergency responders have websites set up to collect donations for hurricane relief. Civic groups and food banks in affected communities are also collecting goods and money to help people who were hurt by the storm.

Local emergency managers are also providing guidance for what resources they do and don’t need. Please take this to heart. The Tennessee Emergency Management Agency, for instance, specifically asks people not to self-deploy to disaster areas and to only donate things requested by local emergency coordinators. FEMA is also encouraging people in the region to coordinate with text messages instead of phone calls to leave phone lines open and to donate cash instead of goods.

Update, September 30, 3 pm ET: This story was published earlier on September 30 and has been updated with new information about the effects of Hurricane Helene and the government’s response.