posted 03-21-2015 08:14 AM ET (US)        

http:/ / www. telegraph. co. uk/ news/ 11487223/ Supertide-2015-Mont-Sai nt-Michel-braced-for-tide-of-the-century-in-pictures. html

Tidal ranges tend to increase at full moon and new moon periods. The tidal range is also amplified when the moon is also at perigee during this time. This phenomenon is called perigean spring tide. See:

http://en.wikipedia.org/wiki/Perigean_spring_tide

The new moon of March 20, 2015 is what is known as a super moon or more technically a perigee new moon.

At the spring equinox the orbit of the earth is not close to perigee with the sun, so that does not appear to be a factor in today's unusually high tide.