Clouds have kept the central interior warmer in the past couple of days, but continued cooling aloft will allow for plummeting temperatures at some point in the next few days. A time-height cross-section of temperature from this morning's GFS forecast shows almost the entire column below -24°C (-11°F) by Wednesday. An airmass this cold (completely below -23°C) is fairly unusual this early in the season, having been observed only 8 times in 65 years prior to November 20 (but 3 times since 2003).
Judging from webcam images today, it appeared that the Yukon River was still moving at Dawson - albeit choked with ice - and the Tanana River was still flowing at Nenana. Here's a video of steam fog over the Tanana River on Thursday morning, when the low temperature was -12°F. (The resolution's not too good, I know - a couple of static shots are below.)