In this case I imagine it is because Alaska is far to the north and remote.

It is common to use "up" for north and "down" for south. I am going up to New York to see my sister for a few days, and then, I am going down to Miami to see my brother. The Oxford Learner's Dictionaries are an excellent resource for non-native speakers. up https://www.oxfordlearnersdictionaries.com/definition/american_english/up_1?q=up meaning 5 to a place in the north of a country They've moved up north. We drove up to Maine to see my father.