According to the National Ocean and Atmospheric Administration's (NOAA) West Coast and Alaska Tsunami Warning Center, a weather event witnessed in New Jersey earlier this month may very well have been a tsunami. This would be a rare event for the east coast of the United States.
Tsunami-like waves were observed along the US east coast during the afternoon of June 13, 2013. NOAA has stated that the derecho weather system that blew through earlier this month likely played a part in the strange wave activity. The weather system moved from west to east over the New Jersey shore just before the suspected tsunami. But they also said that it is possible that the slumping at the continental shelf east of New Jersey played a role.
Most people think of tsunamis as resulting from earthquakes, rather than a simple storm surge, and that is usually the case. But one eye-witness accounting reported in to the Administration told the tale of this tsunami-like event, and has left many officials scratching their heads.
Around 3:30 p.m. on Thursday June 13, 2013, a man named Brian Coen was spear fishing near the mouth of Barnegat Inlet. Earlier in the day around noon, thunderstorms had moved through the area. By 3:30 p.m. the weather was overcast with a light east wind. At approximately 3:30, 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. Coen backed his boat out before being sucked over as well.
At this point, Coen 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 so 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.
One particular feature of tsunamis is that of a strong outgoing current followed by a strong reversal and surge inland. In this instance, a strong current of about 8 miles per hour hit an area that usually only sees 1 mile per hour currents.That was enough for officials to determine that it was not simply a storm surge, common after a storm blows through on the coast. That kind of wave activity is sought after by surfers. This surge exposed rocks that normally are never seen, even in low tide, then rushed back in past them again.
Researchers are exploring whether there may have been a landslide on the ocean floor off the coast, which may explain the wave event and classify it as an official tsunami. Another possibility is that it was an event known as a meteotsunami, a tsunami caused solely by weather. Boats with sonar equipment will be checking the area for ocean floor changes to help solve the mystery.