The Proxigean Tide occurs when the Moon is at its closest point in its orbit to the Earth and in its New or Full Moon phase. At this time, its tidal effect on the Earth is maximum. Tidal gravitational forces vary as the third power of the distance between Earth and Moon, so even a small difference in distance can translate into a big effect. The orbit of the moon varies from a distance of 356,500 to 406,700 kilometers with an average distance near 380,000 kilometers. The variation between the maximum and minimum distances results in tidal force changes of a factor of 1.2 times the average tidal forces.
Visit the Lunar perigee and apogee calculator to calculate these distances yourself!
The times when this will happen often coincide with major coastal flooding events. Between 1997 and 2020 there will be 102 times when this will happen. You can see the list by looking at Fergus J. Wood's book Tidal Dynamics published in 1978 by D. Reidel Publishing company, Dordrecht Holland. There are tables computed by van Flandern at the U.S. Naval Observatory. Here is a short list of the most extreme events based on the time between perigee and syzygy being less than 5 hours:
Date Phase 3/11/2003 New 1/10/2005 New 2/28/2006 New 12/12/2008 Full 1/30/2010 Full 3/19/2011 Full 5/6/2012 Full 6/23/2013 Full 8/10/2014 Full 9/28/2015 Full 11/14/2016 Full 5/25/2017 New 1/2/2018 Full 7/13/2018 New 8/30/2019 New 10/16/2020 New 12/4/2021 New 1/21/2023 New
New Moon is pretty bad because both the Sun and the Moon are on the same side of the Earth, and with the Moon near its closest point to the Earth, the tide- making potential is highest. I will probably not plan to be on the beach on the above dates!
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