The Big Wood begins at the Galena Summit, about 8,700 feet above sea level, formed from churning streams descending the rugged and aptly named Sawtooth Mountains, whose rough-cut, sharp-pointed, snow-covered white peaks line up in a row like a lower jaw of wolf teeth. There, the angry waters join together and then split off into the Salmon River and the Big Wood River at what is surely one of the most beautiful spots on earth.
The Salmon River carves a 425-mile canyon that in places is deeper than the Grand Canyon. Its steep banks of rough rock, at times almost vertical, are covered with bright chartreuse and yellow lichen, while dark, clear water rushes and churns below. Lewis and Clark dubbed the Salmon "the River of No Return," because its current was so strong that they could not paddle back up it. But the Nez Perce, in whose territory the river ran, knew well how to paddle upstream. They were skilled salmon fishermen who lived off the river's rich salmon runs. Later, they also learned to be fine horsemen and deadly riflemen, and they were the last native tribe to be defeated by the U.S. Army. Their last chief on the Salmon River, White Bird, never surrendered nor was captured, but fled to safety in Canada.
I love to fish the Salmon, but it is not open in the winter. The Big Wood is open to fish trout, though only for catch-and-release fishing.
After separating from the Salmon, the Big Wood chortles and snarls for 137 miles, descending the Boulder Mountains in Sawtooth country down to where the riverbanks are low and the casting is easy, just past the town of Ketchum. Along the way, other tributaries join it, including the Warm Springs Creek, whose junction with the Big Wood is an excellent spot to catch trout. Past Ketchum, the Big Wood merges with the Little Wood and becomes the Malad River, which flows into the Snake River and then, like all Idaho rivers, leaves the state to flow into the Columbia River and finally the Pacific.
The Big Wood is not the easiest river to wade into, especially in the winter. The current is strong and the river bottom is covered with large slippery rocks, which makes it easy to lose your balance and fall. I have never fallen in, but if I did, my fishing day would be over. I would have to get out of my wet clothes and go somewhere warm. The river has deep quiet pools, drifting at the edge of the fast current, where the rainbow trout like to relax and grab food, including fishers' flies.
Which leads to the only two rules of fly fishing that cannot be broken: you cannot fall in and you must keep your fly in the water as much as possible. Everything else depends on circumstance.
Rainbow trout are remarkably designed. In the river only their dark backs can be seen, so well camouflaged that you rarely notice them until you hook one. But once the fish is pulled from the water, it is stunning, an almost iridescent rainbow of hot pastel colors.
Big Wood trout are called "cut bows." They have the rainbow trout's typical brilliant colors on their sides, but sometimes also sport a bright red slash of color at their throats. The red slash is the mark of another species of trout of the same genus, the cutthroat, which is abundant in the neighboring Snake River. This means that in the Big Wood, the cutthroats have somehow mixed with the rainbows.
The Big Wood is not stocked by a hatchery—which is significant because hatchery fish are a bit dumb. They don't have the survival skills of wild fish, which has led some to question the value of stocking rivers. Big Wood fish are wild and have the wisdom of experience, as in the summertime they face a constant swarm of catch-and-release fisherfolk who have seen the Robert Redford film A River Runs Through It. In 1925 Hemingway wrote to F. Scott Fitzgerald from Spain and defined his idea of heaven. One of his requirements was a trout stream that no one else is allowed to fish in. Fishing the Big Wood in winter is not quite that, but on a cold enough day it comes close. That's why I like winter fishing. I have the river to myself—and I have to contend with savvier fish. After running the gauntlet of the summer anglers, the fish know quite a bit about artificial flies and those strange creatures standing in the river holding poles. Fish learn.
One factor that makes hatchery fish easier to catch than wild ones is that they are used to being fed regularly and so will eat at any time. A wild trout is a different matter. Scientists tell us that trout like to feed when the temperature is between 50 and 68 degrees. It gets colder than that in the Big Wood, and as the temperature drops, a fish's metabolism slows down and it needs less food. You can still catch fish, though, because they have to eat eventually. I have fished the Big Wood when it was so cold that I struggled to keep my line from freezing and yet the trout kept biting. When the water is cold but the temperature is rising, as is often the case in the late winter, it is prime time for trout to eat. Trout will not eat or breed when the temperature gets above 68 degrees, however. In fact, they will die, partly because the warm water does not have enough oxygen. One of the biggest threats to trout is climate change.