Images Dated 8th April 2004

Glacier crevasses, Canada

Tellot Glacier. A glacier is a huge mass of ice slowly moving over a land mass, formed from compacted snow. The deep crevasses seen here are created when planes of ice within the glacier move past each other, causing shear forces that cause trenches to develop. The mountains at upper left are a section of the Waddington Range, part of the Canadian Rockies. Photographed in British Columbia, Canada

© David Nunuk/Science Photo Library

NA, USA, Colorado, White River National Forest Light snow and quaking aspen trees

USA, Colorado, White River National Forest. Light snow and quaking aspen trees

© Adam Jones / Danita Delimont, Agent

Adam Jones, Aspen, Colorado, Danita Delimont, Environment, Flora, Forest, Grove, Landscape, National Forest, Nature, North America, Park, Path, Pathway, Public Land, Rf, Rural, Scene, Scenic, Season, Snow, Snowfall, Tree, Usa, White, White River, Winter, Wood

Moon dog

Moon dog. Also known as a mock moon, this optical atmospheric effect is seen as bright areas on either side of the Moon. A similar effect is also seen with the Sun, known as a Sun dog or mock sun. It is caused by the refraction (bending) of light by hexagonal ice crystals falling through the atmosphere. If the ice crystals are contained within cirrus clouds it may indicate the approach of a frontal system. Photographed at North Beach, Queen Charlotte Islands, Canada

© DAVID NUNUK/SCIENCE PHOTO LIBRARY