Grand Prismatic Spring

The Grand Prismatic Spring is another of Yellowstone’s iconic hydrothermal features. It is the one that looks like a big orange and blue eye. The spring sits along the Firehole River in the general area of the Upper Geyser Basin where Old Faithful resides. It produces a constant flow of water that flows into and heats the Firehole River. To me, the Firehole River is the most fascinating of Yellowstone’s rivers. It flows from Madison Lake, on the continental divide, 21 miles to the Gibbon River at Madison Junction. What fascinates me, is that it travels through the Upper Geyser Basin, where Old Faithful is located, and past the Grand Prismatic Spring. Those and other hydrothermal features dump their water into the Firehole. This raises the temperature 9-18 degrees Fahrenheit.

The pool filled by the Grand Prismatic Spring is very shallow. It is colored by the brown. orange and yellow bacteria and algae that grow in its pool. The sun highlights its colored features and the water reflects the blue of the sky. Steam rising from the spring adds mystery to the landscape. Though you can appreciate the spring by just giving it a cursory walk-by, paying attention to the details and seeing how the light seems to make them change provides a breathtaking experience.

Here is a link to an image that shows the spring in totality:; I don’t have one of my own to share.

Note: Click on caption to see higher resolution image.

Note: These and other images are available to purchase on my website: or by contacting


Geysers, Hot Springs and Mudpots

Yellowstone is full of hydro-thermal (Hot Water) features; features created when groundwater is heated by Yellowstone’s magma chamber and pushed up to the surface. The geyser, Old Faithful, is the iconic feature of Yellowstone. But that is just one of many. Near Old Faithful is the Grand Prismatic Spring and Morning Glory Pool; 2 famous hot springs. The travertine terraces of Mammoth Hot Springs are constantly under creation as the underlying hot spring bubbles up through a deposit of limestone. The Mud Volcano area has its bubbling mudpots and hot springs. Fumaroles that vent only steam abound.

The interesting thing is that all these features work the same way. A hot spring has a crack or “pipe” that travels underground to the surface. As water is heated, it expands and gets pushed upward. If the pipe has a constriction, it slows the water’s upward movement until enough pressure builds so that the water explodes out of the ground as a geyser. If there is no constriction, the water runs continuously.  If there is a depression, the water creates a pool. If the hot spring doesn’t have a lot of water, it soaks the ground instead of forming a pool. If there is just enough water, it creates pool of bubbling mud. If the amount of water is very small, it forms a fumarole and vents only steam.

Hot springs encourage the growth of bacteria and algae that form mats on the beds of their pools and streams. These mats come in array of colors that make these springs breathtakingly beautiful. Mammoth Hot Springs, whose water flows through limestone, deposits calcium carbonate as the water evaporates forming huge terraces of travertine. In some parts, chemical impurities stain the terraces with beautiful color.

These hydro-thermal features of Yellowstone are a wonder to behold.

Note: Click on caption to see higher resolution image.

These and oter images are available at my website: or by contacting