A Short Story of Seasonal Sand Accumulation and Loss

This sculptured rock is captivating, so I have arranged to visit it several times over the last few years. On September 1, 2015, it looked like this at summer’s end when the sand on Oregon beaches is typically at its highest level, or nearly so.

Summer 2015, much is hidden beneath the sand’s surface


Sand accumulation followed by erosion is a timeless cycle. The summer and fall’s low energy water (e.g., small gentle waves) deposits beach sand, while wild winter surf and backwash remove it. For example, contrast the image above with the same rock on February 1, 2022, when winter’s surf and surge have washed away a remarkable amount of beach sand.

Winter 2022, the lower 2/3 is revealed


The sand removal was so extreme I barely recognized the rock in real-time on the beach. So, to help with the comparison, I’ve drawn a dotted line showing the level of the summer 2015 sand.

Winter 2022 sand erosion exposed the rock’s large lower portion


If you’re like me, it’s not hard to get lulled into thinking of the beach as a stable place, but the sand is constantly in motion, and the cycle of sand accumulation and erosion plays a significant role in the dynamism of beaches. The process is predictable enough to expect beaches to be most expansive in the summer (look up at the distant breakers in the 2015 image—both images are low tide shots) and narrowest in the winter when the underlying boulders and cobbles become exposed by sand loss. (‘Course, it’s a general expectation, not clockwork.)

Earth Story

17 Comments

  1. Thank you for showing us the changes through your lens; beautially captured. The sand has stories to tell. Great observation!

  2. Pretty amazing stuff. I can recall first being impressed at the power of the waves to move sand around when I had a chance to visit a beach near Bandon where I had to climb a goodly sized dune to get to the water. I’m sure it was a time after one of the wild winter storms when the dune down to the beach which, normally a gentle slope, turned into a vertical drop roughly 3′ high. The thought of the power it took to create that solid ledge of sand was quite striking! Wish I could find the pictured evidence but I’m supposed to be working at some organizing and sorting as I type… 🥴

    1. Exactly! The forces that can move that volume of sand are beyond comprehension. Ah, organizing, an eternal struggle, eh? I wish you the best of luck making some headway!

  3. A very interesting choice Steve. Here on Kiawah our beach has no rocks to check its ups and downs, but the tides vary to a huge degree so our waterline is a good indicator of its variability. Loved your choice for this one.

      1. Oh definitely more expansive after storms Steve. The island has done an excellent job of keeping the dune plants healthy to absorb the waters during and after our storms. Then for the few days after our storms the beach becomes huge but it returns to normal shortly thereafter. Pretty amazing to watch nature at work during those times.

    1. It is! The amount of sand moved is beyond comprehension. And I think about all the creatures that somehow make a living in beach sand. About the photos, Thanks! I just checked out your post— same!

  4. What better place to study tidal erosion than Oregon. I am glad you took the time to document it. It is amazing how it changes. So often we say. “man, I think that rock was bigger (or smaller) last time I was here. Love your interpretation for the prompt. Donna

    1. I can’t tell you how many times I passed up an opportunity to document something and then passed it up because I was tired or distracted. So thanks, Donna!

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