A quick check at the Flathead Co. Landfill today (entered into the GBBC). There were about 85 Herring Gulls, 16 Ring-billed, 7 California (FOY), two Thayer's, and two Glaucous (also approximately 2000 starlings). Photos posted.
I checked the Flathead County landfill for gulls yesterday. There were many birds, but not much in the way of diversity. I found 750 Ring-billed, 380 Herring, 25 California and 5 (all first-winter) Thayer's Gulls.