I don't think vision-based FSV will ever reliably handle winter conditions like this. The engineering and QA effort just isn't worth the cost-benefit when you factor in the very small amount of drivers who are consistently exposed to conditions like that. My father, who spent his career commuting to the city on that highway, was disappointed when I explained this to him.
Then a person knocked on a window through the brown wall. It was someone we were to meet at the destination. He greeted us, and told us to come out. We tried to explain we can't just walk all perhaps a quarter mile to the place in this heavy rain, leaving the car left at a roadside. He insisted it'll be a short walk, and gave us no choice. Only when we stepped out, we realized that the car is right in the middle of the premise we were looking for, just couple feet from the main door.
This memory surfaces to my mind in the context of human drivers and inclement weathers; I'm still one piece, but maybe that has more to do with my luck, not necessarily due to myself playing every games extra safe.
It does seem like "something else" is needed for these kinds of low-visibility scenarios -- frankly, when nobody should be on the road.
obviously you try to avoid driving in these conditions when possible, but sometimes a moderate storm is much more intense than forecast and you get caught out. pulling off to the side of a snowy mountain pass doesn't guarantee your survival either.
I suspect there are operating conditions the AVs won't solve acceptably - some of those conditions IMO are also conditions where we should not accept a human to solve acceptably. In general I feel we have a lackadaisical culture around driving that encourages/excuses unsafe behavior, and is overoptimistic about people's ability to drive well.