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 aurora borealis, or northern lights, illuminates the night sky above Lake Superior in Michigan's Keweenaw Peninsula on Nov. 3, 2015. The red beach is the result of light from the photographer's head lamp. Photograph taken at North Canal Township Park, where the Keweenaw Waterway meets Lake Superior.