greenish-black caterpillars covering a desert shrub near sand dunes

4wd arid atv board camp caterpillars climb colorado covering creek dark desert dunefield dunes endemic escape family float footprints footsteps full getaway great greenishblack heat hike hills hot lightning medano morning mountains national natural nature overcast park play preserve recreation river road sand shadows shrub sky sled slide splash stars storm stream summer swim thunder travel unique vacation wade wilderness wildlife windy