As someone who likes overland travel and natural hazards, this is *chef's kiss*.
My one criticism is on the blizzard weather condition. I would like it to be clearer if blizzards force the con check (or not) even if you are wearing a snowsuit. That was one part that felt subtle enough to miss, and would be worth highlighting.
Otherwise, this is a great supplement with a little bit of everything. It perfectly fits the mechanical load of shadowdark, and every part of this feels inspired. I was excited to read from one page to the next.
Fantastic work!