Monstrous hurricanes Helene and Milton caused so much complex havoc in the U.S. states of Florida and Carolinas that damages are still being added up, but government and private experts say they will likely join the infamous ranks of Katrina, Sandy and Harvey as super costly $50-billion-plus killers.

Making that even more painful is that most of the damage – 95 percent or more in Helene's case – was not insured, putting victims in a deeper financial hole.

Storm deaths have been dropping over time, although Helene was an exception. But even adjusted for inflation, damages from intense storms are skyrocketing because people are building in harm's way, rebuilding costs are rising faster than inflation, and human-caused climate change are making storms stronger and wetter, experts in different fields said.

"Today's storms, today's events are simply vastly different from yesterday's events. One of the things that we're seeing is the energy content that these systems can retain is significantly greater than it used to be," said John Dickson, president of Aon Edge Insurance Agency, which specializes in flood coverage. "The weather seems to be, in many cases, moving faster than we as a society are able to keep pace with it."

The $50 billion mark for direct losses is a threshold that differentiates "truly historic events," said Adam Smith, the economist and meteorologist who runs the list out of NOAA's National Center for Environmental Information in Helene-hit Asheville, North Carolina.

Only eight hurricanes reached that threshold. Smith said he thought Milton and Helene have "a very good shot" of joining that list.

The first $50 billion hurricane was Andrew in 1992. The U.S. went 13 more years before Katrina topped the damages chart, then seven years until the third costly whopper, Sandy. Helene and Milton would make seven in the last seven years.

There's three categories of damage: insured damage, uninsured damage and total economic cost. Many risk and insurance firms only estimate insured losses.

Homeowner insurance usually covers wind damage, but not flood. Special insurance has to be bought for that. Flood insurance coverage rates vary by region and storms differ on whether they cause more wind or water damage. Helene was mostly water damage, which is less likely to be covered, while Milton had a good chunk of wind damage.

Of the top 10 costliest hurricanes as compiled by insurance giant Swiss Re – not including Helene or Milton yet – insured damage is about 44 percent of total costs.

But with Helene, Aon's Dickson estimated that only 5 percent of victims had insurance coverage for the type of damage they got. He estimated $10 billion in insured damage so doing the math would put total damage in the $100 billion to $200 billion range, which he called a bit high but in the ballpark. Insured losses for Milton are in the $50 billion to $60 billion range, he said.

Risk modeling by Moody's, the financial services conglomerate, put a combined two-storm total damage estimate of $20 billion to $34 billion.

Karen Clark and Company, a disaster modeling firm that uses computer simulations superimposed on storm and insurance data, wouldn't give total damage estimates for the storms. But the company figured insured losses alone were $36 billion for Milton and $6.4 billion for Helene.

Much of the damage is because of flooding. Studies show that hurricanes are getting wetter because of the buildup of heat-trapping gases from the burning of fossil fuels. Basic physics dictates that clouds hold 7 percent more moisture for every degree Celsius, and that falls as rain.

And when it comes to flood insurance, many homeowners in risky areas find it's too expensive, so they don't buy it, said Karen Clark, who founded her namesake firm. But when a storm hits them, she said "all of us as taxpayers, we're going to pay it because we know there are going to be federal dollars coming into those areas to help people rebuild. So all taxpayers, we're actually paying for people to live in risky areas."