You have to agree that seeing dunes and snow-capped mountains at the same location sounds awesome. Now add to that a creek that has waves and you get a full picture of how amazing the Great Sand Dunes NP is. It is like being on the beach and in the mountains at the same time. I guess that's why the park is so popular with families with small kids.
Water in the creek is usually pretty warm, even during winter, as the creek is shallow and, therefore, sun can warm it up quickly. Kids and adults alike love to splash in the stream as it has waves created by mounds of sand that form and fall in the creek bed. That creates water surges, similar to the action of waves at a beach. Beware that creek is a seasonal phenomenon and might be non-existent during warm summer months.
Kids, dogs, adults - everybody loves to play in the Medano Creek:
Playing in the dunes is also lots of fun!
Here I am rolling down the dune:
And here is Anil sliding down on his ass... :)
After splashing for a bit in the creek we went for a hike to "The High Dune" (198 m/650 ft), which is actually not the highest dune in the park. It is called "high" as it appears the highest from the parking lot...
Hiking in the sand is hard, but the views are so great that it is worth the effort:
After around 1.5h we made it to the top of the dune:
Going down was much faster as we could slide, roll or run down :)
A word of advice: If you go hiking in the dunefiled, wear closed shoes as sand can get unbearably hot!
Other posts about the Great Sand Dunes NP.