Full Moon Over Nooksack Ridge, North Cascades, Washington
The full moon rises over Nooksack Ridge in Washington's North Cascades just after sunset. The mountain glows because of alpenglow, a natural phenomenon that lights mountains with almost white light about a half hour after sunset. The almost violet sky comes from the Earth's shadow cast onto particles high in the atmosphere.

Mount Rainier, Shadow on Clouds (Aerial View)
Mount Rainier casts its own shadow on a thick bank of clouds in this aerial view taken from over Pierce County, Washington.

Mount Rainier and Glory (Aerial View)
Mount Rainier's shadow and a bright glory are visible in this aerial image. Glories form when sunlight scatters backwards in clouds or mist, and therefore are only visible from airplanes or mountain peaks.

Snow Geese Lined Up, Skagit Flats, Washington
Thousands of snow geese (Chen caerulescens) walk and fly in formation over a farmer's field near Mount Vernon, Washington. More than 30,000 snow geese winter in the area, feeding on grass and other plants before flying north for the summer.

Irisation/Iridescence in Clouds, Utah
Colorful irisation appears in the clouds above Bryce Canyon in Utah. Irisation, also called iridescence, typically forms when the sun shines into clouds that are forming. The colors are most vibrant when the water droplets that make up the clouds are uniform in size.