This stuff drives me nuts. Instead of this article, they should publish one about dressing correctly, not going if worried, getting hand warmers, not painting your chest and going shirtless, etc. If a person wants to be stupid, let them. The consequences, like the choice, are theirs.
These people live in the area and if you don't, do your research.
They most certainly make cold weather gear made for sub zero temps.
My gear would normally be 2 pairs of long underwear, 2-3 pairs of hunting socks, tennis shoes, 3/4 inch insulated rubber boots, a pair of jeans,1-2 heavy sweaters,a full snowmobile suit, a heavy fur water resistant jacket I called my Eskimo jacket, a pair of wool gloves,a pair of duck feather filled gloves over top of those, the kind with only the thumb, full ski mask, ear muffs,a heavy wool cap over that, a heavy wool scarf and sometimes goggles. That got me through some serious subzero temps to -30+, with windchills around -80.
If I'm going to be sitting ,I'm bringing my hunting seat with me and hand warming packs.
When I'd come in my lower layers would actually be soaked from sweat.
As long as you stay dry you're good. If you get wet and it soaks through, you're ******.