The fall singletrack season is officially over, at least in the Salt Lake Valley. Shaded trails or those on aspects on the northern side of the compass are now a muddy or snowy mess (see above). I'm sure some will ride them, but it's bad trail etiquette (due to erosion) and terrible on components.
The basic problem is the lack of solar insolation. There's simply not enough energy to melt snow and dry soils on northern aspects. The white stuff is lingering on those aspects even in the foothills now. You can ride up a wide south facing dirt road, but elsewhere, the going is tough.
Of course, all is not lost. This is just a sign that it is time to switch to skis.