Onsen lover in Zao

I will be visiting Zao Onsen town next week to visit onsens. I prefer outdoor (rotemburo) onsen in nice settings amongst snow and rocks if possible. I understand that the large Dai onsen is closed winter time, but are there any others? I'm willing to pay and use hotel onsens as well.
I'm grateful for an tips in this matter - Domo arigato

I like the Shinzaemon no Yu:
http://www.japan-guide.com/e/e7928.html

The baths are outdoors, but relatively small and without outstanding views. But the atmosphere is nice and the water outstanding.

That is the best outdoor bath in Zao I am aware of. Some hotels may have even nicer ones.

Even though you prefer outdoor baths, I also recommend to visit a small communal bath house. The Kawarayu Public Bath is unique. Not only does it stand right on top of the source, it also has a rather unique tub.

Thank you for the information, Uji-san!
Shinzaemon no yu is now on my onsen list :) together with Genschchi roten nu yu and I will also go to a couple of the public wooden ones. They look quite similar to the ones in Nozawa onsen - which I love! waku-waku!!