This 'N That: Southeast Tidal Flooding; Late Tropical Storm

A car makes its way through King Tide flooding recently in South Florida.
Photo by Joe Raedle/Getty Images via Weather Underground.

The southeastern United States has had their hands full for more than a week now with so called "nuisance flooding," in which high tides have caused repeated bouts of minor flooding along the East Coast.

The cause was a combination of astronomically higher tides this time of year, an offshore storm that drove water toward shore, sinking land masses, and climate change.

These are very similar to the factors that caused the severe flooding in Venice, Italy over the past week.  

Some of the East Coast flooding was damaging, especially during the height of the offshore nor'easter a few days ago in North Carolina.

Along the Outer Banks, officials were almost ready to open main roads like North Carolina Route 12, damaged by Hurricane Dorian earlier this year, when the latest storm undid much of that work. They'll have to start over.

Down around Miami, there's not much in the way of destruction, but the tides have run above normal daily for at least a week. The land isn't sinking there, so a lot of this is climate related.

As I've said, higher tides usually come in the autumn around Miami and northeasterly winds have driven added water ashore. But before sea levels began rising decades ago, this minor, daily nuisance flooding wasn't nearly the factor it is now.

That's because these minor "sunny day floods" are just so much more frequent now.  The amount to streets and parking lots having several inches of water on them. But these repeated salt water inundations, though not deep, can eventually cause a lot of damage to buildings and infrastructure.

Remember, salt is corrosive, which is why our cars rust so easily here in Vermont. We're always driving on salted roads in the winter.

As Weather Underground's Category 6 blog notes, citing work by NOAA oceanographer and nuisance flood expert William Sweet:

"Sea level in Miami has risen about six inches in the last 25 years, according to Sweet. That's roughly twice the global average for seal leel rise since 1993 of about 3 inches as calculated by the University of Colorado Boulder - not because of subsidence, but because of shifting ocean and atmosphere patterns that are pushing more water into the coast.

TROPICAL STORM SEBASTIEN

Hurricane season in the Atlantic Ocean is coming to a close - the season officially ends November 30, but you can still get an occasional tropical storm or hurricane after that.

There is one last hurrah going on out there. Tropical Storm Sebastien formed the other day in the central Atlantic Ocean.  It's been slowly gaining strength, even though it is rather disorganized.

Forecasters think Sebastien might strengthen into a hurricane in the next couple of days as it heads northeastward over open water.  The good news is it's very unlikely to affect land.  It's awfully late in the season for a tropical storm to form where it is - far to the northeast of Puerto Rico. But it's not unheard of.

It's good that what will likely be the final sendoff to the 2019 hurricane season will be so harmless.