The angle of repose at Silver Lake Dunes

Miniature Landscapes by Neil Weaver Photography

I shared the photo below of what Neil dubbed “The Great Sand Pyramid of Silver Lake Dunes” back on December 17, 2020. Like the ones in the photo above, the lines are so crisp & clear that they look computer generated. Sleeping Bear Dunes is another shifting dune complex, and they explain that the reason that the sand on shifting sand dunes looks the way it does is due to wind & something known as the angle of repose:

Active dunes gradually advance over time. In some places trees and telephone poles have been buried in drifting sand over a period of several years. A common question is “How fast are the dunes moving?” Rates of sand movement vary from one place to another and from one year to the next. At the Dune Climb the average rate of advance has been about 4 feet (1.2 meters) per year over the past few years.

Direction of sand movement also varies from one place to the next. The shapes of dunes reveal the direction of the winds. Dry, loose sand can take on a maximum slope of 34 degrees, known as the angle of repose. As sand piles up on an unvegetated dune, the leeward (downwind) slope approximates the angle of repose, while the windward slope is more gradual. Ripples in the sand show a similar asymmetrical shape.

Dune sand moves primarily by a process called “saltation”, literally “jumping”. Wind forces grains of sand to roll, collide with other grains of sand, and in subsequent collisions some grains bounce into the air, are driven downwind as they fall, and upon landing strike other grains to produce a chain reaction. On a windy day you can see a hazy zone of sand moving just a foot or two above the ground.

Neil took the photo above last year in late December & shared “One of the many things that I love about hiking around the sand dunes is finding miniature landscapes created by the strong winds. The textures and lines compose a true natural work of art!”

Indeed!! See lots more of Neil’s work on Facebook and view & purchase prints, calendars & photography workshops on his website!

The Great Silver Lake Pyramid by Neil Weaver Photography

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Isle Royale Rangers … and a Kayak

Julie off Hawk Island by Carl TerHaar

Here’s a sweet article in the Northern Express about the all-women team of park rangers at Isle Royale National Park for you to check out. It has nice profiles of each ranger and begins:

John Muir and Theodore Roosevelt. Everett Townsend and Walter Fry. Franklin Delano Roosevelt, Richard Proenneke, and Ansel Adams. Since the inception of the national parks in the late 1800s, the men who carried the banner of wilderness preservation also wrote the history of their movement, often missing the crucial role women played in protecting America’s wilderness from the Industrial Revolution and the raw material extraction that revolution demanded.

At Isle Royale National Park, the lower 48’s least visited but most revisited national park, an all-women team of park rangers reminds us that all it takes to work in nature is a passion for conservation and a love for the outdoors.

“It wasn’t intentional at all,” says Katie Keller, lead ranger at Isle Royale, when we inquired about how the team came to be. “Hiring for the parks is different every year. So we were just as surprised as the visitors when we had all-women rangers two years in a row.”

Karl took this way back in 2011. See lots more in his Isle Royale National Park album and view & purchase his work at Mackinac Scenics.

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