This week’s supermoon was more than a spectacular sight in the night sky. It nudged up sea levels, leading to areas of coastal flooding along the East Coast.
Such inundation offered a glimpse of the new normal in certain low-lying areas as sea levels rise because of climate change.
Coastal sections of South Florida and New England were among those immersed in ocean water on Monday and Tuesday during high tide cycles. From Palm Beach to Miami, the Weather Service hoisted coastal flood advisories cautioning that tidal levels were running about a foot above normal “due to the occurrence of the super moon.”
In New England, the Weather Service office in Boston said the combination of “very high astronomical tides” and a weak coastal storm would result in a water nearly a foot above normally dry land at high tide.
Other coastal areas along the East Coast were also experiencing coastal flooding, including Charleston, S.C.
Every year from November through February, the highest tides — called “king tides” — press onto the shores during full moons. This is a result of the enhanced gravitational pull from the full moon as well as Earth’s being closest to the sun in its orbit (at perihelion). The tides get even higher during supermoons, because that’s when the moon is closest to Earth (at perigee).
Coastal flooding during such astronomically high tides has been increasing over time because of climate warming, which raises sea levels. “Recent sea level rise ensures that when king tides occur they increasingly cause localized flooding,” the Union of Concerned Scientists said in a blog post.
Since 1960, sea levels have risen about 6 to 8 inches along the East Coast. Meanwhile, the National Oceanic and Atmospheric Administration has documented a 300 to 925 percent increase in “nuisance flooding.”
Such flooding inundates areas that previously flooded only during big storms. It makes roads impassable, overwhelms storm drains and seeps into structures.
Such flooding is only expected to worsen and affect more land area in the coming decades as sea levels are projected to rise as much as several feet by the end of the century.
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