Thursday, October 29, 2015

Boston's "wicked pissah King Tide"

A "King Tide" is the highest type of non-storm-related tide in any given location.

It's an annual thing. The date varies, but is always at a high tide around the time when (1) the Earth's slightly elliptical orbit brings it closest to the sun (perihelion); (2) when the Moon's elliptical orbit brings it closest to Earth (perigee).

The combined and enhanced gravitational pulls "... result in the largest tidal range seen over the course of a year." (Wikipedia page)

Yesterday, (Oct 28 2015) Boston experienced a King Tide.

Boston normally has about a 10'/3m tide range, but this King Tide would run about 2.5'/0.75m higher than normal. This isn't a huge amount --- it's not "massive flooding" or anything like that.

But it is, coincidentally, about what an average, non-King/non-storm high tide will be like in a few decades, due to global warming and ocean rise. (The waters off New England have already risen by 4-5"/10-12cm since record-keeping began, with most of the rise happening in the last few years.)

The Boston Harbor Association --- a nonprofit focused on stewardship of the harbor, its 34 islands, and the surrounding shorelines --- and saw this King Tide as a teaching opportunity to "give a glimpse of Boston's average tide sometime around or after mid-century."

They asked for volunteers to take photos of vulnerable spots during what they christened the "wicked pissah King Tide;" they plan to use these to illustrate the point.

I went to the Boston waterfront yesterday to snap photos near Long and India Wharfs (popular tourist spots near the New England Aquarium, and where the various ferries and sight-seeing boats depart).

Long Wharf was awash:

 photo PA280001_zpsjgifujjd.jpg

 photo 20151028_123846_zpspilirqkn.jpg

Medium-res video clip: https://drive.google.com/open?id=0BweMPb5u6AP1amZIUFBvQUFDQjQ

Low-res vid clip:


Ferry departure:
 photo 20151028_123703_zpskec0tg0k.jpg


Low-res vid clip:



India Wharf was a little more protected, but roughly the same:
 photo short_zpsltn4pb7h.jpg


Low-res vid clip:


Again, the point of the exercise isn't to show tsunami-type flooding or anything like that --- but to drive home the point that the ocears are on the rise, and that rare, once-a-year high tides today will be happening twice every day in just a few years.



No comments:

Post a Comment