when are you going?
We once traveled to Alaska in October, many years ago. We were in snow-less Fairbanks and needed to get back to Anchorage to fly home, so bought train tickets to Anchorage, as I recall. (We were debating between driving and train, if my memory serves me correctly, since we wanted to see the scenery of Denali at least passing through.) Then it snowed mega-bigtime, I believe the train route was actually cancelled that day, roads were temporarily closed too, and we had to fly to get there in time.
This is just anecdotal, I can't imagine snow could shut down transportation that often.