Many of us learned about the threat and true devastation that can be caused by “riverine flooding” for the first time last week. 

With the rescue and cleanup still ongoing, it’s too early to have a precise tally of the tremendous damage wrought by Hurricane Helene in North Carolina, West Virginia, Tennessee and Georgia. 

But it’s been enough time to learn riverine flooding can hit inland mountain towns as hard as any storm surge slams the coast. Moreover, those towns are often less prepared as a front page New York Times story today noted.

The initial cost to private insurers and the federal and state government will likely be dwarfed by longer-term costs to change building codes and raise insurance premiums. 

A decade ago Hurricane Sandy slammed into the coast of my home state, New Jersey. My parents were forced to flee and had to relocate for half a year while their hometown was cleaned up. Later they had to rebuild. 

According to SigTech MAGIC, an analytical tool used by quants, Sandy cost as much as $70 billion in damage and also led to significant increases in insurance premiums, the adoption of refined catastrophe models and extensive revisions to building codes. 

The SigTech MAGIC analysis showed Sandy caused: 

–Insurance premiums to rise $5,000 to $10,000 on average

–Codes to mandate higher elevation standards for buildings

–The use of flood-resistant materials in construction

–Hospitals to install temporary generators and boilers

–New regulations on the location of HVAC units 

–Additional requirements in NYC on buildings over five stories

A larger question in the aftermath of Helene will be where and how towns should be reconstructed, according to Robert S. Young, Director of the Program for the Study of Developed Shorelines, a joint Duke University/Western Carolina University venture. 

Young pointed out mountain towns were located in river valleys so manufacturing facilities could use water power and rivers for transportation.

In a LinkedIn post, he wrote: “Does it make sense to put everything back in areas where it will still be exposed? Raising entire business districts is impractical and also sort of weird. These are tough questions that I fear most will not want to think about.” 

“There is a growing acknowledgement that we live in a new normal. We must rethink how and where we live with the floodplain (and how big that floodplain really is). I hope there may be some opportunities to re-envision our mountain towns.”

Technology has changed a lot since Hurricane Sandy. AI programs can help pinpoint and assess risks. We can quickly query Magic to rank the states and estuaries at risk of flooding or pull together a list of historical floods. 

For example, North Carolina suffered: 

Hurricane Floyd (1999): Catastrophic flooding

Hurricane Matthew (2016): Significant river flooding

Hurricane Florence (2018): Severe riverine flooding 

Sadly, what AI technology cannot do is rebuild homes much faster.