Snake River
The Snake River is an old and venerable river. It's ancestral forms drained most of Western North America into what is now San Francisco Bay (and various other points along the west coast of North America.). For 70,000,000 years (or more,) it has been the migration route into the interior of Western North America, and the drainage route out, as well.
It has survived in one form or another through the uplifting of the Rocky Mountains, The Sierra Nevada Mountains, The Pacific Coast Ranges of California, and The Cascade Mountains of Washington & Oregon. As the mountains of the west were uplifted, and the western volcanoes spread their lava fields it has changed it's course many times. It has swept over Nevada, Idaho, California, Oregon, and parts of southern Washington, (perhaps - at one time very long ago - it even touched the margins of the Colorado River drainage and fed the Gulf of California).
It's constant head-cutting, (as various mountain ranges were born,) has stolen the waters of many rivers and streams. This process of "stream piracy" continues today as it is head-cutting into the Madison River drainage at Reynolds Pass, and into the Gallatin River Drainage in the Northwest corner of Yellowstone National Park. It is also making inroads into the headwaters region of the Yellowstone River in the Thoroughfare region, (at two oceans plateau,) of southeastern Yellowstone Park. Perhaps in the distant geological future it will capture the Madison River and The Yellowstone River (and Lake,) turning north-central North America into a giant waterless desert.
IS IT ANY WONDER THAT THERE IS SUCH DIVERSITY IN FISH AND FISHING IN THE WEST YELLOWSTONE AREA?
Currently, the Snake River is one of the master streams of the western and southern portions of Yellowstone National Park. It is also the master stream for all of Southern Idaho. It's origins lie in two distinct areas: 1), along the flanks of the Continental Divide in the West Yellowstone, MT / Island Park, ID region, and 2), along the flanks of the Continental Divide in the Jackson, WY region. This drainage of the southwestern Yellowstone Plateau has given the visiting fisherman two fantastic fishing streams: The Henry's (North,) Fork, & The South Fork of the Snake River.
HENRY'S (NORTH) FORK, OF THE SNAKE RIVER
Born in the seep springs and snowmelt above Henry's Lake adjacent to the origins of the West Fork of the Madison River, The Henry's Fork tumbles quickly to the valley floor of the Island Park uplift and caldera. This volcanic basin is rich in nutrients from the soils, and the discharge of many small tributaries, (and the discharge from inside Yellowstone Park through Big Spring & the seeps at Malfunction Junction.) It flows into Henry's Lake as a simple mountain stream and fills this ancient glacial basin with the cold clear waters that has made the lake famous.
With the discharge waters from the lake and the confluence, at Mack's Inn, of Moose Creek, and then the Buffalo River at Pond's Lodge the Henry's Fork becomes a gentle, (though large,) river that holds the potential for great fishing. The impoundment of waters in the Island Park Reservoir has limited the discharge to gentle runoff, and contributed to the silting of this river that was, because of it's age and topographic setting a mature stream, already depositing a heavy bed-load, (and also drowned many excellent trout waters of the Trude [yes, that Trude,] Ranch.
As the river enters its mature and meandering sections it flows through Railroad Ranch and under the Osborn bridge. This is the section that draws fishermen from the world over to the hatches and the Fish. It then wanders through sagebrush flats, joins the waters of the Warm River and out of the caldera to Ashton, Id. Continuing to gather tributary streams, (such as the Tetons,) it grows in size and speed as the lava bedrock controlls more and more of it. It finally joins the South Fork to the east of Pocatello and Idaho Falls.
SOUTH FORK, OF THE SNAKE RIVER
The glaciated margins of the southwestern mountains in Yellowstone Park have many high mountain meadows and intertwined drainages that are the remnants of the retreat of the mountain glaciers. Two Oceans Plateau is one of these areas. It is in this region that both the Yellowsotne River, (a tributary to the Missouri River,) and the Snake River, (a tributary to the Columbia River,) arise and flow to each of the great oceans that border the North American Continent.
The water from Two Oceans Plateau join with the waters debauching from Lewis Lake, (the Lewis River,) to form the South Fork of the Snake River near the south entrance to Yellowstone Park, (near Moose Falls). It travels a course through Grand Teton National Park and the Lakes of that beautiful region. Whereas the North Fork drains the west side of the Tetons, the South Fork drains the east side, providing fisherfolk a chance to admire these distinctive mountains from both sides in a single day.
The south fork continues to Palisades Reservoir, and then via a magnificent tailwater fishery to join the North Fork at their confluence. The waters above the reservoir provide typical, (though large,) riffle and run sections along with meandering meadow sections with deep pools. The waters below the reservoir are large and filled with deep pools and long stretches that are bed rock controlled. Very much like the Madison River these lower sections are best explored by drift boat, and best experienced and appreciated from the bank.
It is still possible to catch "Fine Spotted Snake River Cutthroat Trout" in this section of the river. The population is slowly being eradicated by other introduced species, just as has happened in the waters of the Henry's Fork.