Those who think waterfalls should be visited during the spring and summer, have to see Colorado's fantastic winter falls. One of the most famous winter spots is The Fang, a 50 m (165 ft) tall waterfall in Vail. This waterfall is actually more popular in the winter than in the summer as many people enjoy climbing it. It is rather difficult though, and you need special equipment.
If you happen to be near Denver, you can see Bridal Veil Falls, located on I-70 past Idaho Springs. This is a very popular photo op stop.
Seven Falls is called "The Grandest Mile of Scenery" in Colorado. You'll see Pike's Peak, granite Pillars of Hercules, and The Seven Falls are superb in the winter as it features seven frozen leaps down the granite.
Helen Hunt Falls is easily accessible in the winter as it plunges down Cheyenne Canyon and is located in just a mile from the parking lot.
Rainbow Falls is located just beneath Manitou Avenue near the lovely town of Manitou Springs.
There is also a stunning Hanging Lake near Glenwood Springs, which is definitely worth visiting. However, mind that it's a 3-hour drive from Denver and hiking to the lake might be rather tough in the snow.
Finally, it's pretty amazing to see a curtain of ice in Box Canyon outside Ouray. The ice resembles melted candles hanging off the rocks. There is also more entertainment in Ouray Ice Park to be checked out.