A very brief history and description of the land: The Yellowstone area has a history of colossal volcanic events, the most recent occurring 640,000 years ago, producing an ash zone from the West coast to Texas. These explosions caused a collapse of the ground, producing the caldera. By comparison, the 1980 eruption of Mt. St Helens produced an ash zone of just 19 miles.
Deep beneath Yellowstone’s caldera (2-3 miles), magma from the still active volcano heats groundwater that rises to the surface through fissures in the rocks. Depending on the fissures’ constriction, water emerges at the surface as a geyser or hot spring.
The intense blue color in the hot springs are due to sunlight being scattered by fine particles suspended in the water. The yellow, orange, green, and brown colors encircling the hot springs and lining the runoff channels are caused by thermophiles – heat loving bacteria – that live at extreme temperatures, often well above boiling.
Simply put, early rumors and legends described Yellowstone as “a place where Hell bubbled up”.
Bubbling mudpot: Sulfuric acid producing, rock dissolving bacteria = awesome.
Fumaroles (steam vents) have a small amount of water that boils away on its way to the surface leaving only steam to escape.
The sights of Yellowstone are certainly remarkable, but so are the sounds of all this water and air exploding and belching from the Earth’s interior. This hydrothermal action creates quite a raucous, from the roaring thunder of geysers, to hissing of the fumaroles, bubbling of hot springs, and soupy plopping of mudpots.
And then there are the smells of Yellowstone. The pungent aroma of sulfer. Mmmm, rotten eggs.
We didn’t let a little rain spoil the day!