Alaska [1] is divided into two time zones, but nearly all of the state—from Southeast Alaska [2] to the western tip of the mainland—is on Alaska time, one hour earlier than Pacific time or four hours earlier than the East Coast. The western Aleutians are on Hawaii time, two hours earlier than Pacific time. British Columbia [3] and Yukon are on Pacific time.
So when you go from Prince Rupert [4] to Ketchikan [5], Dawson to Eagle [6], or Beaver Creek to Tok, you gain an hour; from Skagway [7] to Whitehorse [8] you lose an hour.
Links:
[1] http://www.moon.com/destinations/alaska
[2] http://www.moon.com/destinations/alaska/southeast-alaska
[3] http://www.moon.com/destinations/british-columbia
[4] http://www.moon.com/destinations/british-columbia/prince-rupert
[5] http://www.moon.com/destinations/alaska/southeast-alaska/ketchikan
[6] http://www.moon.com/destinations/alaska/the-interior/eagle
[7] http://www.moon.com/destinations/alaska/southeast-alaska/skagway
[8] http://www.moon.com/destinations/western-canada/yukon/whitehorse