Zapata Falls near the Sand Dunes is really spectacular to see in the winter time when the whole thing freezes into a massive ice column. I was leaving the dunes one day and saw the sign for Zapata Falls off to the left going South on Hwy 150. I figured I'd check it out and I was SO glad that I did. It was amazing to see and the ice was so clear that you could see the water flowing underneath it. It's definitely worth the time if you're making the trip to the dunes.