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You might think that when a tsunami takes place, such a huge wave would be obvious, but the sea can be mysterious, the kind of enigma that HP Lovecraft once wrote about when he penned a line about the secret lore of the ocean. And scientists from NOAA, the National Oceanic Atmospheric Administration, still have to work to understand it. At the moment, they're trying to understand why ocean levels across the East Coast fluctuated rapidly last month without warning.
Here's Bradley Campbell of Rhode Island Public Radio.
BRADLEY CAMPBELL, BYLINE: On June 13th, North Kingstown harbor master Ed Hughes had a really unusual evening. Reports of the ocean acting strangely interrupted his harbor commission meeting. Hughes and others raced to nearby Wickford Harbor to see what was happening.
ED HUGHES: I got down there pretty much towards the end of it, but I could see where the boats were still being pulled - like with a lot of pressure, being pulled from where they were.
CAMPBELL: He says the water went rushing out to the sea and then reversed and started to rush back into the harbor like a river. Hughes says he had no clue what was happening.
HUGHES: It was just so unique to see it. I mean, there was five of us just shaking our head, going, this is different.
CAMPBELL: News of the curious incident at Wickford Harbor made its way to scientists at the University of Rhode Island's Graduate School of Oceanography. Professor of geophysical fluid dynamics Chris Kincaid says they quickly pulled up data from the National Oceanic and Atmospheric Administration. Sure enough, the gauges from North Carolina to Maine showed an anomaly.
CHRISTOPHER KINCAID: And right about at low tide on this day, on June 13th, you can see the water level just drops right off the table.
CAMPBELL: Kincaid says the drop and corresponding rise in water level was tsunami-like. But fellow geologists at his institution looked at seismic records, nothing. So Kincaid says his peers pulled up weather data for the day and bingo. NOAA had numerous reports of severe weather in a concentrated area in the mid-Atlantic. It was a phenomenon known as a derecho.
KINCAID: I've heard people describe them as beautiful and incredibly scary.
CAMPBELL: Derechos are essentially a long band of thunderstorms that bring high winds. Kincaid and fellow scientists say the winds could have slammed into the ocean, pressing down on its surface and causing it to respond with tsunami-like waves. But is that what really happened? Kincaid says it's one possibility. The head of NOAA's tsunami program, Mike Angove, is suspicious. He says it's investigating the possibility of an underwater landslide happening in the Hudson Canyon off the New Jersey coast. Angove says a NOAA tsunami reporting buoy in the area recorded a significant change in ocean level.
MIKE ANGOVE: That's really maybe the most interesting thing in this whole deal is that if it was a weather-induced tsunami that happened in the shelf region, you wouldn't necessarily expect for it to register at that dart buoy, which is located in very deep waters.
CAMPBELL: NOAA dispatched a research vessel to take detailed images of the Hudson Canyon. NOAA will look for any changes. For North Kingstown harbor master Ed Hughes, though, he isn't so sure scientists will ever find out what happened and that's just fine with him.
HUGHES: I'm willing to bet you, the bottom line is going to be we think this is what it was. You'll never get an answer. I don't think you'll ever get an answer. And that makes it way cooler.
CAMPBELL: Hughes says the unanswered questions just add to the wonderful lore of the ocean. For NPR News, I'm Bradley Campbell in Providence. Transcript provided by NPR, Copyright NPR.