If you have a four-wheel-drive it doesn’t mean you can drive just like you normally would. It just means you crash harder when you’re going faster.
Stay in the ruts and don’t pass a lot. Find a place where you feel like you have control and try to stay in that lane
Turning on your flashers and driving 10 to 15 miles an hour on the freeway may be an advisable way to handle fog in California but it’s a hazard and downright dangerous to everyone around you on the freeway during a snowstorm. If everyone else wants to go 30 to 40 or 50 probably you should go 30 to 40 or 50 as well. If you can’t do this you should try surface streets
If you are afraid to drive in it, park your car and call an Uber