The water is cold and the fish are in their winter hiding places. The slower moving water and deeper pools are where most fish spend the winter months. There is not as much available food so the fish tend to hunker down a little. That said the fishing can still be pretty good this time of year. A lot of big fish are caught on the Truckee in the winter months. I had a pretty good day yesterday my client had two really nice Rainbows to the net and a couple of big white fish. The California side is going to have some access problems pretty soon due to snow pack so keep an eye on that. The Nevada side is usually a little safer bet this time of year mostly because it is a little warmer and access is not as much of an issue. Keep an eye on the flows they can start to yo-yo due to rain and run-off. The best winter flows are less than 400 CFS. Look for warmer days and fish in the afternoons for best results for sure. Down size your flies a little and cover every lane in the pool you are fishing. The fish will not move as much to eat this time of year so it is important to cover the water more methodically. Nymphing is going to be your best bet. Get your flies down to the bottom in the deeper slower runs. Try some sort of a Bead head fly in a size 12- 16 as the lead fly and a much smaller dropper like a Baetis or a Midge pattern in an 18 - 20.