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.
The polar vortex may be gone, but another extreme event is coming. Space weather experts say northern states may be able to see the aurora borealis, or northern lights, Thursday and Friday morning. We're hoping, said Joe Kunches with the National Oceanic and Atmospheric Administration's Space Weather Prediction Center in Boulder, Colo.