Tuesday, June 25, 2013

Scientists Confirm Tsunami Hit Narragansett Bay

A small tidal wave hit the Rhode Island coast on June 13.
The June 13 wave was slightly smaller

A small tsunami hit the Narragansett Bay earlier this month, causing sea levels in the bay to rise and fall several feet within 20 minutes.

A straight line thunderstorms - called a derecho - apparently triggered a tidal wave on June 13, a University of Rhode Island scientist told The Providence Journal . A derecho is a straight line of thunderstorms that sweeps across the country in an eastward direction and can cause hurricane-force winds.


Instrument readings confirm that on June 13 at 4 p.m. a tidal wave hit Rhode Island. The abnormal tidal flow stretched from South Carolina to Maine, affecting sea levels and causing damage - albeit minor - across the eastern seaboard. 

In Wickford Harbor, the swift ebb and flow of the tides pushed boats around with enough pressure to pull a cleat from a dock and rip out three stanchions, a Wickford Yacht Club employee told the Providence Journal.

Abnormal tidal rises lasted for about 4 hours on June 14, according to a National Oceanic and Atmospheric Administration tide gauge in Newport. The instrument recorded a normal rise and fall from 12:01 a.m. June 13 to midnight June 15 except from about 4 - 8 p.m. where graph jigs, seismometer-style, recorded jagged vertical strokes that gradually blend back into the normal sine-wave pattern.

Although the tsunami's reach stretched across the East Coast, area scientists said the hardest place hit by comparison was Rhode Island. 

EDITOR’S NOTE: Another URI expert thinks the tsunami may have been caused by an underwater landslide. My nephew Chris O’Reilly worked on tsunami modeling as part of his final work for his master’s degree.

He told me he had discussed this event with one of his professors whose specialty is sediment. That professor thought the likely cause was a underwater landslide. Chris told me that it was odd to attribute the tsunami to a storm since storms aren’t known to generate tsunamis.

But, he suggested, “It is possible that the low pressure from a storm can influence slope instability on the seafloor and trigger in an underwater landslide.” – W. Collette