The Fall River is also fishing pretty well. Maybe not quite as strong as the Metolius, but like the Met, the Spring Fed waters provide some more consistent water temps for the fish and the hatches.
In December and improving in January expect Midges, small Black Winter Stones, Blue Wing Olives and possibly some mixed caddis here and there that could provide for a decent but isolated afternoon bite.
We’ve been having our best success on Micro Streamers on a Euro Nymph Rod and Leader set up. Nymphs have been good too, especially Perdigons and Eggs and Zebra Midges.

It is going to get frigid cold in about 3 or 4 days here, with a big arctic air mass dropping over Oregon starting Sunday and lasting 3 to 5 days. I do think if you’re prepared for it, both the Spring Creeks will be fishable, but dress warmly, bring some hot tea, a change of clothes and let people know where you’ll be and when you are returning.