Sue Vilardi was shocked when she heard the news.

“I didn’t think anything like that happened around here,” said the Stafford Township resident. “I didn’t know it could happen not from an earthquake.”

But according to the National Oceanic and Atmospheric Administration(NOAA), it was true. A tsunami struck the Jersey Shore earlier this month.

On June 13, strong thunderstorms moved into South Jersey around noon. By 3:30 p.m., the weather was overcast with a light east wind, according to officials. Around that time, officials say Brian Coen was spear fishing near the mouth of the Barnegat Inlet. Coen spotted an outgoing tide with strong currents coming towards him. According to Coen, the heavy waves continued for about two minutes until the rocks in the submerged breakwater were exposed, forcing Coen to back his boat out of the area.

Coen then spotted a large wave, approximately 6-feet from peak to trough, coming across the inlet. The wave was so powerful that it swept two people off a rock jetty and into the water on Long Beach Island. They were both rescued from the water and treated for non-life threatening injuries.

After hearing several reports from witnesses, NOAA officials confirmed on Monday that a tsunami had struck the area that day.

“This event produced a tsunami that was recorded at tide gages monitored by the West Coast/Alaska Tsunami Warning Center (WCATWC),” they said. "The tsunami was observed at over 30 tide gages and one DART buoy throughout the Northwestern Atlantic Ocean."

Officials say the source of the tsunami is “complex” and “still under a review.” They also say however that the earlier storm system that struck the area was a possible cause.

"The 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," they wrote.

Officials also say that the "slumping at the continental shelf east of New Jersey" may have played a role. They continue to investigate.