Tuesday, July 13, 2010

Metaripples?

At a very low tide at Boundary Bay, you can walk out over the sand flats for perhaps about a mile before you come to the surf. All the way out you alternately cross dry or drying pans, and long, shallow pools oriented roughly parallel to the shore.

You walk across fields of ripples of various shapes, sizes,

textures,

and degrees of water content.

But what you are also doing, as you travel across countless smaller ripples,

is walking across a broad field of long-wavelength ripples, shown here extending from the shoreline to the giant yellow push-pin. That's about as far out as I have ever walked. The brown/blue switch in water colour is an artifact of the composite satellite imagery. The yellow horizontal line is the border separating Tsawwassen, BC and Pt. Roberts, WA.

As the tide recedes, the water flows southward and eastward, in some pinch-points quite powerfully, through the channels between the megaripples. Perhaps metaripples?

6 comments:

Kyna said...

When I first saw the title of this post, I thought it said 'Meatripples'. Sounds like a disease. "Can't make it to your party, I got the Meatripples'. Glad to see your post was about something different.

Hugh said...

Oh yeah, meatripples is nasty.

Eskarina said...

Thanks for the good post Hugh. I sure wish more people could see it as more than a sandy place to put a beach umbrella.
I love it best at low tide on sunny fall or winter days (rare, very rare) when the shorebirds (and the raptors who love them)are cruising through.

Hugh said...

Eskarina, Thanks. I certainly agree. I sort of blindly walk through the beach umbrellas, on my way to "out there." The farther you go the more magical it gets.

Melissa said...

Beautiful. Amazing, the similarity between your photos and the dunes of Lencois Maranhenses. http://ngm.nationalgeographic.com/2010/07/brazil-dunes/ribeiro-text
What wonders are at work.

Hugh said...

Melissa, Wow, what a picture.