Yes, your concerns are valid. I'd be concerned at risking alienating myself from the family especially for such a special moment in their lives. If you're living in a region where you were getting clobbered by snow over the weekend, I'd say that it sounds like winter conditions aren't unusual to begin with and people probably know how to handle their vehicles in it.
Did you make it safely there and back? Were you able to give the gift that you wanted? I noticed mention that if it were this coming weekend you'd been able to pick out a gift?