This is generally caused by cold, dry air. I've also heard that plastic food and water bowls can be a culprit, though I'm not sure how much truth there is to that. My girl had the 'snow nose' her first winter with us. It went away when the weather warmed up and since then she has never had it happen again. We heat our home with forced air, natural gas, heat and have a whole house humidifier. Since her first winter here I have adjusted the humidity in the house up a bit for the winter which may be why she hasn't had the pink nose in the winter again ... or it could be that she is just older and the dry winter air doesn't effect her as much.
One thing you could try is applying a product called Bag Balm to her nose every so often to moisturize. I used it the first winter Jazz was with us and it seemed to help a bit. The only issue with it was that she didn't care for it being applied to her nose, and she liked to lick it off once it had been applied. Even so, it did seem to help a bit.