Apostle Islands Ice

May 14, 2014



Photographer: Neil Libby
Summary Authors: Neil Libby; Jim Foster

Shown at top is a stunning view of ice cascading down the sandstone bluffs at Apostle Islands National Lakeshore, on the shores of Lake Superior. The pale bluish and greenish colors are caused by non-spherical ice crystals scattering sunlight. When ice or snow is thick the crystals composing it both scatter and absorb light. Longer wavelengths (red and yellow colors) of the visible spectrum are more readily absorbed than are the shorter wavelengths (greens and blues). If the ice or snow is sufficiently thick, all of the longer wavelength colors will be extinguished, allowing only blue and green light to emerge.

As a result of a very cold winter conditions in 2014, mainland ice caves were opened for the first time in five years (bottom photo). Thousands of visitors flocked to see these gems in February, March and early April. Photo taken on February 3, 2014.

Photo details: Camera Maker: NIKON; Camera Model: COOLPIX P100; Focal Length: 9.2mm (35mm equivalent: 52mm); Aperture: f/6.3; Exposure Time: 0.0020 s (1/500); ISO equiv: 160.