PROVIDENCE, Rhode Island -- According to NOAA, tsunami-like waves were observed along the US east coast during the afternoon of June 13, 2013. NOAA says that "the source is complex and still under review, though the coincidence at several gages with strong atmospheric pressure fluctuations indicate that it is at least partly generated by meteorological causes."
The tsunami event occurred in close conjunction with a weather system labeled by the National Weather Service as a low-end derecho which propagated from west to east over the New Jersey shore just before the tsunami. NOAA speculates that it is also possible that the slumping at the continental shelf east of New Jersey played a role.
This event produced a tsunami that was recorded at tide gages monitored by the West Coast/Alaska Tsunami Warning Center (WCATWC) at over 30 tide gages and one DART buoy throughout the Northwestern Atlantic Ocean.
The highest observations were recorded at Newport, Rhode Island with a peak amplitude in wave height of 26 centimeters (just over 10 inches), followed by Kiptopeke, Virgina at 25 cm, and Atlantic City, New Jersey at 24 cm.
Additional peak amplitude observations were recorded in Massachusetts as high as 22 cm, Connecticut (11 cm), Maryland (12 cm), Delaware (12 cm), New York (19 cm), Bermuda (6 cm), and Puerto Rico (7 cm).
NOAA was able to obtain a first-hand description was provided by Brian Coen who observed the event at Barnegat Inlet in New Jersey:
Around 3:30pm on Thursday June 13, 2013, Brian Coen was spear fishing near the mouth of Barnegat Inlet in New Jersey when the outgoing tide was amplified by strong currents which carried divers over the submerged breakwater (normally 3-4 feet deep). This strong outrush continued for 1-2 minutes and eventually the rocks in the submerged breakwater were exposed. Brian backed his boat out before being sucked over as well.
At this point, Brian noticed a large wave coming in, approximately 6 feet peak-to-trough and spanning across the inlet. The upper 2 feet of the wave was breaking. This wave occurred in conjunction with a reversal of the current such that even though the tide was going out, a strong surge was entering the inlet. This surge carried the divers back over the submerged reef and into the inlet from where they were picked up. On the south jetty three people were swept off the rocks which were 5 to 6 feet above sea level at the time. At least two were injured requiring medical treatment. There was no more strong activity after about 5 minutes.
Just yesterday, on June 24, 2013, NOAA observed a magnitude 6.6 earthquake in the Mid-Atlantic Ridge at 6:04 p.m. EDT. But that earthquake was not expected to cause a destructive widespread tsunami.