We soon eagerly exit Interstate 70 again for Hwy 50, our highway of choice to cross the Rockies, and the Continental Divide. The climb follows the Gunnison river upstream through a narrow ravine, which occasionally  widens into fertile, hidden flats where the red dogwood and yellow willow appear to set the river on fire. Long and narrow working ranches with weathered but elegant ranch houses are set into clefts in the valley sides.

The summit is at 10,149 feet and then we slowly wind our way down to the Great Sand Dunes National Park at 8500' elevation.

This unusual Park features the product of the winds blowing relentlessly against a fold in the Rockies, and the power of water to concentrate the sand back at the foot of them. The giant sand dunes are the tallest in America at 830 feet tall. They ripple along the mountain's base for thirty miles, distinct against the snow capped peaks above, the shades and shadows constantly shifting as the light changes. 

It reminds us of our adventure crossing the Sahara desert in 1989.

Our campsite faces the mountains, and in late afternoon a series of thunderstorms roll over us. We sit in the front seats with cocktails, watching the dunes briefly turn white with hail. Lightning repeatedly strikes the dunes. On the crests of the dunes wind whips up the sand, like the spray flung off a giant wave. As the storms pass, a herd of deer graze their way across the cactus scrub in front of us and vanish into the Pinon pine forest.

Unusually for us, we take an early morning hike, frost still outlining the footsteps of deer on the trail, up to a dune overlook. Then down onto the dunes, to the strange river that flows over the sand, continually returning sand back to them from the mountains, before itself sinking and vanishing into the sand.