Washington, D.C. king tide, April 19, 2011. (Jamal Kadri via U.S. EPA)

Thanks to an opportune alignment of the Earth, moon and sun this weekend, some of the highest tides of the year arrive in Mid-Atlantic coastal areas. These so-called ‘king tides’ may offer a glimpse of what will become the new normal in coming decades as sea levels rise.

What exactly is a ‘king tide’? Writes the Maryland Department of Natural Resources (DNR):

The term ‘king tide’ is a non-scientific term used to describe naturally occurring, exceptionally high tides that take place when the sun and moon’s gravitational pull align making the oceans “bulge”

(The moon is doing its part this weekend: reaching full phase almost exactly when it makes its closest approach to Earth, achieving the so-called ‘super moon’ status).

Environmental organizations are using  the king tide as an opportunity to show coastal residents what sea level rise from climate change might look like.

“Climate projections show that if we continue on our current [greenhouse gas] emissions pathway, by the end of the century what is now a rare water level may become typical,” writes Melanie Fitzpatrick of the Union of Concerned Scientists (UCS).

The Environmental Protection Agency’s Greenversations blog puts it this way:

Who knew you could go back to the future with a trip to the coast? It’s true though. King tides are exactly that; a glimpse to what our future holds with climate change and our rising seas.

Want to see the king tide yourself?  Here’s a table of high tides from the Maryland DNR:

High tides this weekend in Maryland; king tides in bold (Maryland DNR)

A quick perusal of tide tables indicates high tides will generally about half a foot to one foot above what’s typical.

Consider snapping some pictures and sharing them with Maryland’s King Tide Photo Initiative on Flickr.

“The images highlight places that will become increasingly vulnerable to flooding, higher storm surges, eroding shorelines, and saltwater intrusion under ongoing sea level rise,” writes UCS’ Fitzpatrick.

Fitzpatrick adds the images are “a valuable repository for planners and managers in all levels of government.”

EPA’s State of the Environment Flickr group is also soliciting king tide images (tag any “King Tide”).