Hi Goldfinger,
Yes, the buildings are heated but probably kept a little cool to save fuel costs as this was a public building rather than a home. Judging from the photos of the outdoors, it was perhaps anywhere in the range of -10 to -40 degrees C. at the time. It was clear, sunny and calm in the middle of winter which indicates a high pressure area. This means that it would have undoubtedly been well below zero at the time. This would mean that everyone had taken off their heavier outer layer and just left on their lighter under layer with the zippers open while they were inside. People usually dress in layers up north as it is more efficient and comfortable than one single, heavy garment.
The depth of the cold up north is something that is a bit difficult to imagine if you have lived only in the south. It is no myth or exaggeration that it can kill you in a very short time if you are not prepared for it. However, if you are prepared for it, life in the winter in the remote parts of Canada is every bit as engaging, interesting, and busy as anywhere else. Oddly enough, in Canada, the winter is when the heaviest and most productive work is done in the resource extraction industries. This is mostly because the frozen landscape provides much easier access and movement for heavy equipment and people than in the summer. Also, there are no mosquitoes, black flies, and other blood sucking denizens of the north during the winter.
Hope this helps,
RHammer
