Replying to all comments:
Thanks! The lowest temperature that I think I experienced over there was -43C (when I check outside myself)...However, it could be colder at times when I didn't check as my car thermometer couldn't show temperatures below -40C. And frequently the thermometer was dropping to -40C and staying there for a couple of hours. The area is amazing and in the winter time, it is pretty desolated, especially during the Christmas time (when I was there). No traffic whatsoever. But if you don't like extreme cold don't even bother. During that trip, I reached Tuktoyaktuk and touched the Beaufort Sea ...well, not really the sea but its ice cover.
That morning when I took this photo the temperature was around -38C...so a relatively hot sunrise

In terms of photos from that trip with frozen forest alone---yes, I have those, too. Will post them here at some point when I dig them out. Have a good weekend!
Artur