A high-resolution camera mounted on NASA's Mars Reconnaissance Orbiter has snapped pictures of unusual, almost perfectly circular sand dunes on the Red Planet's surface.
Bizarre sand dunes on Mars are 'almost perfectly circular,' and scientists don't know why : Read more
Aloha ,
Following the story about Mars and it's 'round 'sand dunes:
Looking to our own earth for the answer, we can take the Extreme Winter Temps and How the Drift Form in Minnesota as an example. In my time spent in that Freezer [as cold as -44 that froze my car to the snow/ice/grass/and dirt].
On one winter's night when I had to be out and returning with a howling wind following my car, I encountered drifting Snow and Dirt building Drifts across my path. At one bridge I had to step on the gas to burst through a 'wall of Snow' that 'matched the opening of the bridge . I had no means of knowing just how thick this wall of snowpack was or what was hidden on the other side but there was no time to stop or go around it. There was no stopping or I'd be stuck [this was before cellphones to call for help]. As i hit the 'wall' it turned out to be only about 12 inches thick and nothing was waiting for me as the packed snow fell all around me.
Drifting Snow in Minnesota can happen even in the cities of well plowed streets. One day driving in Austin [Hormel Town], my car happen to drive 'up the snow-packed surface of a drift made by the strong winds blowing at my back. These winds 'Pack' the surface hard as the road itself and you are climbing the drift, unawares of the gradual climb. At the end of the drift, where the wind blown snow ceases to travel is where a rude awakening is to surprise you . this is where the Hard Pack has not yet happened and the snow is soft as powder and your car suddenly drops into this soft bed of snow. In my case, the car was now 4 feet higher then the road's surface! To the wind blow side, snow was as hard as a rock, to the downwind tail, soft as a bed of feathers.
My thoughts as to those 'Drifting Dunes' is that the same presses is happening.
A final note:
Since temps are So Extreme there, the same packing and windblown drifting is what we are seeing.
Mahalo,
Mark Baker
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