June 2013 Meteotsunami Captured by NOAA/NOS Coastal Water Level Stations

Tuesday, 16 December 2014
Kathleen Bailey, Christopher DiVeglio and Ashley Welty, NOAA Washington DC, Washington, DC, United States
On June 13, 2013, a north-south oriented, long formation of strong storms passed eastward over the New Jersey coast. Three hours later, while the weather was calm, a sudden runup of water along the New Jersey and New England coasts was witnessed despite no nearby seismic activity. Post-event analysis revealed that a rare meteotsunami impacted the East Coast of the United States. The strong pressure jump associated with the storms generated an ocean wave that became amplified when the speed of the storms reached the speed of the wave, creating resonance. The wave approached the Mid-Atlantic shelf break and reflected back, explaining the time lag between the passing storms and the incoming wave. The National Water Level Observing Network (NWLON) stations maintained by the National Oceanic and Atmospheric Administration (NOAA) National Ocean Service (NOS) Center for Operational Oceanographic Products and Services (CO-OPS) measured strong water level oscillations at several stations along the eastern seaboard. The detided one-minute data show the tsunami signal with maximum amplitudes ranging from 0.16 m at Nantucket Island, MA to 0.61 m. at Newport, RI. The Narragansett Bay stations captured the meteotsunami wave propagating northward and diminishing towards the innermost part of the Bay. The Atlantic City, NJ station captured the 3.2-mb pressure jump in the six-minute barometer data from the passing storms as well as the incoming wave that hit three hours later with a maximum amplitude of 0.47 m. Along the U.S. coast, harbor shape and orientation contributed to the strength of the tsunami wave, and some stations that were in shadowed areas did not measure a strong signal despite being in an area of measurable impact. Meteotsunamis pose a threat to the U.S. coastline, and without high-resolution observations and models these events cannot be quantitatively forecasted. NOAA does not currently have an operational warning system but the June 2013 meteotsunami provides an excellent case study for identifying setup conditions and timing of an impact from a reflected wave.