You mean carefully get to the nearest settlement as soon as possible? Some of these storms can last for days at a time. Stopping to wait it out in the middle of nowhere, especially if you don't have a full tank of fuel to keep the car warm for extended periods, is a pretty scary situation.

While I think it's plausible to teach a self-driving car to drive in snow (like I do, generally following in the tracks of the cars ahead of me), I honestly think this is one of the best justifications that cars should continue to have steering wheels and pedals: Because automated snow driving is going to take a lot longer to become a solved problem than fair weather driving.