NOAA: E. Coast Cities Should Expect Flooding 25 To 130 Days/Year, Even W. "Moderate" SLR By 2050
EDIT
Shoreline tides are getting progressively higher. A soon-to-be-published report obtained by NPR predicts a future where flooding will be a weekly event in some coastal parts of the country. "The numbers are staggering," says oceanographer William Sweet, at the National Oceanic and Atmospheric Administration. "Today's storm will be tomorrow's high tide," he says, referring to how high coastal water rises. "A storm [such as we experienced] along the East Coast of the United States this weekend, that will be a high tide at some point in the future, whether that's two or three decades or eight decades, we'll see, but it's coming."
This new report sets out to give communities a clear guide to prepare for coastal flooding. "We find that minor flooding starts on average about a foot and half above high tide," says Sweet, "Moderate flooding starts about two and a half feet above high tide, and major flooding starts about four feet."
That's what people can expect now; it gives them a margin of safety, and for the most part communities have been built to handle that. But here's the thing: As high tides get higher, that is inexorably reducing the margin of safety. In fact even without a storm, high tides already are flooding cities like Miami and Norfolk, Va. And now NOAA's latest calculations portray a future where this kind of "sunny day" flooding will become a lot more frequent.
NOAA's calculations of future high tides assumes two "intermediate" forecasts of how much sea level will rise — from one and a half feet to three feet by 2100. It by no means assumes some of the more severe scenarios should the ice sheets in Greenland or the Antarctic melt. Even with intermediate rise, by 2050 cities on the Atlantic would see high tides flooding the streets 25 to 130 times a year. By 2100, it could happen almost every day. These frequencies will be influenced by weather patterns like El Nino and prevailing winds, but over time they'll occur more often from rising tides alone as sea level gets higher.
EDIT
https://www.npr.org/sections/thetwo-way/2018/03/05/590901652/new-report-predicts-rising-tides-more-flooding