Bobby Socks Trees in Yellowstone National Park.
Bobby socks trees! Dead lodgepole pines near some hydrothermal areas look as if they are wearing bobby socks. The dead trees soak up the mineral-laden water. When the water evaporates, the minerals are left behind, turning the lower portion of the trees white. Fall turned the grasses a golden color, accentuating the scene.
Known as Altocumulus Standing Lenticular (ACSL) or Altocumulus Standing Lenticularis clouds, they are associated with waves in the atmosphere that develop when relatively stable, fast moving air is forced up and over a topographic barrier that is oriented more or less perpendicular to the direction from which the upper-level wind is blowing. This deflection creates a gravity wave downwind of the topographic barrier not unlike a wave you might generate by throwing a pebble into a pond. When sufficient moisture is present above mountain-top level, ACSL clouds develop within the crest of these mountain waves where the air is rising. ACSL clouds are continually developing and dissipating in the vicinity of the wave's crest and immediately downwind of the crest, respectively. That is why they appear to remain stationary (hence the name) even though winds are swiftly (sometimes very swiftly) moving through the entire cloud. They are most often seen in the winter or spring when winds aloft are typically the strongest.
Grain elevator on the Rocky Mountain front, Montana.
Winter scene in the Lower Geyser Basin, Yellowstone National Park.
Boulders encased in ice and snow in the Lamar River, Yellowstone National Park.
Boulders and fall trees frozen in the Lamar River, Yellowstone National Park.
Aspen trees overlooking the Lamar River, Yellowstone National Park.
Yellowstone in Winter, Northern Range
Yellowstone in Winter, Northern Range.
Winter scene, Yellowstone National Park.
Barn and outbuilding in the Gallatin Valley, Montana.
Raven in Yellowstone National Park. This raven has had a "vest" containing a radio transmitter placed on him, as part of research into the travels and other behavior of ravens in the Park.
Spasmodic Geyser
Spasmodic Geyser, in the Upper Geyser Basin, Yellowstone National Park.
Upper Terrace, Mammoth Hot Springs
"It was this big!" Pelicans on the Madison River, Bear Trap Canyon, Montana.
