Yellowstone National Park
Grand Loop Drive:
Driving Time: 40 minutes
Distance : 21 miles
We begin in Mammoth Hot Springs at the Albright Visitor Center, where the Yellowstone Association offers a wealth of interpretive brochures and books, and park rangers offer advice to make your forays more enjoyable.
From the visitor center, the road to Norris climbs south past the Mammoth Terraces, a magnificent set of travertine steps. The natural chemistry and plumbing that go into the building of these terraces are quite marvelous. Rain and snowmelt seep deep into the ground and are eventually warmed by heat radiating from the large chamber of magma, or molten rock, lying just 2 to 3 miles beneath the earth. At those depths, the waters come into contact with carbon dioxide released from that same magma chamber. As the carbon dioxide dissolves in the hot water, it makes a weak carbonic acid solution, which in turn dissolves the vast limestone formations lying under the surface as it seeps downslope. Once the solution reaches open air, carbon dioxide escapes. That, in turn, causes calcium carbonate to precipitate out of the water, solidifying again as a material known as travertine.
The travertine in some parts of Mammoth Terraces is building up at a rate of 2 feet per year! At Minerva Terrace, roughly in the middle of the Lower Terraces, look for massive vertical columns of travertine. These may remind you of stalactites that hang from roofs of caves; in truth, they're formed in much the same way.
The fanciful colors you will see in many of these thermal features are not caused by travertine, which is white, but rather by masses of primitive bacteria and algae living in the water. Thus, the shades of Yellowstone's geothermal features tend to be colorful when the feature is"active" (when water is flowing), but change to a dull white or gray when changes occur under the Earth that stop the flow. You can get a better view of the terraces at their base, from parking areas located on your right several hundred yards past the Mammoth Hot Springs Hotel and General Store, as well as from the Upper Terrace Loop Drive, above the terraces on the right, two miles from the Albright Visitor Center.
Just under 2 miles beyond the turnoff for the Upper Terrace Loop Drive is a stark jumble of travertine rocks called The Hoodoos actually pieces of old hot spring terraces that tumbled down the mountain in massive landslides. From here, you will continue to climb for another mile, passing the bright orange and yellow rocks of Golden Gate, as well as a particularly nice plunge of Glen Creek known as Rustic Falls, and finally topping out at sage-covered Swan Lake Flat. Three-foot-deep Swan Lake, like similar shallow ponds nearby, does indeed play host on occasion to trumpeter swans.
Beyond Swan Lake Flat, the road passes Sheepeater Cliffs (once home to Yellowstone's only resident Native Americans); winds through Willow Park, an excellent place to spot moose; passes Apollinaris Spring where some of the park's first visitors used to stop for a drink of mineral water (not recommended now); and in another mile reaches Obsidian Cliff on the left (east) side of the road. While moss and lichen cover much of the rocks of Obsidian Cliff, dulling them, it is still easy to catch glimpses of the black, shiny glass, formed by rapidly cooling lava, that was so prized by early Native Americans for making points and tools.
Make your next stop at the stark, somewhat lifeless-looking flank of Roaring Mountain, also on your left (east). Roaring Mountain takes its name from a steam vent near the summit of the peak (just one of many steam vents, or fumaroles, scattered across the mountain) that used to emit a rather startling howl, easily heard by travelers on the nearby wagon road. Roaring Mountain seemed to run out of things to say around the mid-1920s. Like so many thermal features in Yellowstone, though, it may strike up another round of noise-making sometime in the future.
Four miles past Roaring Mountain, plan a visit to the Museum of the National Park Ranger, located on the road to Norris Campground. It contains a fascinating collection of exhibits that chronicle the history of the National Park Ranger from the days of the army soldier to modern times.
Details mentioned in this article were accurate at the time of publication