|Tuesday's King Tide swamping Charleston, South|
Carolina Tuesday. Photo from WCIV.
Tides reached near record highs in the southeastern United States, despite the absense of any storms. Usually, tides that come close to record heights come during hurricanes or other severe coastal storms as hurricane winds push a storm surge inland.
This time, no storms. And hate to say it, but climate change had a role in Tuesday's coastal flooding.
Around the time of the full "supermoon" in the autumn, when the moon is a little closer to the Earth than usual, tides are higher than normal. This is nothing new.
Making it a little worse, winds were from the east along the southern Atlantic seaboard, which drove water toward the coast, making the tides a bit higher than they normally would. Again, this is fairly normal and has happened before. It was just bad luck that the wind was from the east, rather than the west, during this extra high tide.
Had climate change not been around, this would have been a high tide with some coastal flooding but the flooding would not have been too extensive.
Global warming has driven sea levels up by, on average 8 inches since the late 1880s. It's worse along the U.S. East Coast for reasons I'll explain below.
Tides just several inches deeper than in the past don't seem like much, but in flat coastal areas like those around South Carolina, southeastern Virginia or Louisiana, a few extra inches of ocean water can go surprisingly far inland and cause a lot of flooding. The land just doesn't increase in elevation much as you go inland from the beaches.
Making matters worse along the East Coast is that a massive Atlantic Ocean current heading northeastward away from the United States has slowed. That current tends to draw water away from the East Coast.
With the current slowing, less water flows away, so it collects near North America more. Again, we're only talking about a few extra inches of water, but as noted it adds up.
The result, was Tuesday's King Tides, that scored in the Top 10 highest on record in some locations. This is really odd, because as I said, there were no hurricanes around to create a storm surge. Most of big memorable tidal floods are associated with hurricanes.
As Washington Post's Capital Weather Gang notes, "Seemingly overnight, spurred by sea level rise, we've entered an era where king tides compete with hurricanes in the water level record books."
Tuesday's high tide in Charleston, South Carolina peaked at 8.69 feet. That was short of the record high of 12.56 during the epic Hurricane Hugo in 1989, but still high enough to be in the top 5 biggest tides on record for Charleston.
The high tide Tuesday at Savannah, Georgia reache 10.43 feet, the third highest on record. Only two high tides there were slightly higher - those during hurricanes in 1940 and 1947.
Flooding was reported in other areas besides South Carolina and Georgia. Some water invaded Miami Beach, and minor flooding was reported near New Orleans.
This type of non-storm coastal flooding is going to keep getting worse.
Already, a NOAA study has concluded that "nuisance flooding," the type that shuts down very low lying roads and sneaks into parking lots, streets, basements and storm drains, has gone up between 300 and 925 percent along all three U.S. coasts since the 1960s.
Annapolis and Baltimore, Maryland have had the biggest increase in these nuisance tidal floods. The NOAA report says this problem will keep getting worse and worse as sea levels increase.
This can't be good for coastal residents.
Here's how the Miami Herald described Fort Lauderdale on Tuesday:
"Just east of the Intracoastal Waterway in Fort Lauderdale, even before the highest tides, seawater flooded the street outside Shooters Restaurant and lapped at sidewalks.
'I love everything about the neighborhood and the location and the restaurants nearby, but it seems to be getting worse,' said Robert Owen, who purchased his condominium at the nearby Tides at Bridgeside Square about seven years ago. 'It can't be good for property values.'"
No, it can't Mr. Owen! And as the high tides worsen and become more frequent along the coasts, this is going to be a nightmare for insurers, and low lying towns who face expensive work to hold back the tides, plus lower tax revenue from lower property values or people just moving away from the enroaching water.
Meanwhile, another round of King Tides is expected this morning. The tides shouldn't be as bad starting Thursday.