After leaving the relics, we followed the old, faint track further north. Weaving down one ridgeline only to switch back and follow another in almost the opposite direction. Driving probably 300 meters back and forth for every 100 meters north. And soon we were in the true dunes. Where the sand dunes are still alive, still creeping northeast by blowing the sand from their tail to their head.

A few inches a year.

By the bones that have been exposed at other sites, I would guess it takes close to a century for an entire dune to pass over one spot.

The bared ground left behind is usually a neat place to snoop. Seeing what has been left exposed after 100 years.

'Course, today was a lousy day for that, since there was still an inch or so of new snow covering the ground. But the heeler sisters were still quite hyper, their desires to run and play by the old cars greatly hindered by the abundant prickly pear cactus.

Here, there is no cactus.

So while I walked, they ran and chased, barreling up one side of the dune, then down to run up the other.

Stopping occasionally to wonder why I wasn't joining in.

We weren't the only ones on the dunes. Several sets of rabbit tracks in the fresh snow, and one recent set of coyote tracks, which the sisters darted off to follow, shoving their muzzles into a footprint to inhale deeply, then snorting to clear the nasal membranes for the next whiff, a few steps farther down.

And on a warmer slope, in the sun and protected from the cold wind, the little maskless heeler found life.

But there were still things to do this morning. A sick deer to find. I tried following the sisters up the shady side of the dune, back towards the truck, only to find the sand frozen solid.

With the upper few millimeters recently thawed. Like climbing an oiled ball. Those of us with padded, hairy feet with toenails ran up and down the dune with the greatest of ease, while those of us in boots and bare skin couldn't get up the slope at all.

Even on all fours.

Had to loop around and climb a sunny slope to get out of the basin behind the dune. And head back to the truck on the nearby stabilized ridge.