These are 5 position alpha-numeric codes comprising the d series. All other level II codes and descriptors are approved and maintained jointly by the alpha-numeric editorial panel (consisting of CMS, the Health Insurance Association of America, and the Blue Cross and Blue Shield Association).
Alaska: Although Alaska enjoys a high volume of aurora activity, its cruises are not often mentioned as northern lights cruises. During the Alaska cruise season, it's rarely dark enough for the lights to be visible.
Alaska cruises tend to explore the same southeastern ports of Ketchikan, Juneau, Skagway and Sitka. Yet to immerse yourself in the land of sled dog, Arctic tundra and northern lights requires a trip to Alaska's northwest interior. Cruise lines have the answer: the cruisetour.