alt Hacker News> the number of bicycle commuters plummets towards zero
That's proof that there's either a lot of progress to be made, or the local culture just isn't as tolerant to the cold.
Cycling around -10 works just fine if the roads have been taken care of (which, in your example, doesn't seem to be case, as apparently they're covered in ice).
With decent infrastructure, the difference between cycling 10 degrees above and 10 degrees below freezing is a matter of outfit.
Ice isnt a product of cold. It is actually rare on roads in the high north. Ice requires melting and re-freezing, and gets more slippery when wet. Ice is a problem when the weather bounces back and forth around freezing. Each city will be very different, but those near the great lakes are famously impacted by ice storms. See https://en.wikipedia.org/wiki/List_of_ice_storms