Trout above Treeline
Tips & tactics for fishing southwest Montana's alpine lakes.
High-mountain lakes are a different beast. Not the polite, predictable trout stream we’ve grown accustomed to, with its riffles and runs like signposts guiding us to fish. No, alpine lakes are enigmatic; they shimmer with mystery—glass-calm one moment, wind-tossed the next, offering trout that feed with maddening inconsistency. And yet, when they come alive, it can feel as if the fish gods have momentarily dropped their guard, gifting you with native cutthroat, rainbow, brook, and even golden trout.
No matter where you go, you don’t simply go to a mountain lake. You earn your way there.
Here in southwest Montana, we’re spoiled for choice. The Absaroka-Beartooth Wilderness alone holds more than 350 fish-filled lakes, scattered across stream drainages along the northwest border of Yellowstone. The Gallatin and Madison ranges are peppered with alpine gems, while the Crazy Mountains offer the kind of remote, punishing hikes that make a trout feel like a well-earned reward. Meanwhile, a trip into the Beartooths means jagged peaks and crystal-clear waters.
But no matter where you go, you don’t simply go to a mountain lake. You earn your way there. Whether it’s a quad-burning climb or a strenuous bushwhack, there’s always some kind of pilgrimage involved. And when you arrive, breathless and questioning all your decisions, you’ll stand at the shore, watching the water for signs of life, and wonder: Did I hike all this way just to get skunked?
Selecting a Lake
A mountain lake can be lifeless or teeming with trout. The difference? Usually a combination of elevation, stocking history, and food availability.
Do your research. Montana Fish, Wildlife & Parks maintains an online database of stocking records, which will tell you what species have been planted there, in addition to when and how many. But don’t just check that a lake has fish—check when they were stocked. If the last drop happened four years ago, those trout might be big and healthy. If it happened last summer, you might be dealing with a bunch of overeager juveniles.
Elevation matters. The sweet spot tends to be between 7,000 and 10,000 feet. Anything higher, and winterkill becomes a concern—some lakes freeze so solid and so long that trout simply don’t make it. Food supply matters, too. Midges, caddis, leeches, and freshwater shrimp all fuel a thriving fishery. Inflow and outflow streams help.
When fishing nymphs below an indicator, start with at least five feet of tippet. If you’re not getting grabs, go deeper.
Once you get to the lake, consider where the fish are. Trout like to move along structure, depth changes, and with the natural currents of the lake. If the water is clear enough, you can see these depth transitions from shore. If possible, cast along the edges of submerged logs or boulders.
If you’re fishing nymphs, make sure you have enough tippet under your indicator. A nymph dangling six inches below the surface isn’t going to do much unless fish are actively rising. Start with at least five feet of tippet, and if you’re not getting grabs, go deeper. If the wind picks up, let it drift through the chop like something helpless.
When to Go
If you’re hiking up in May with a fly rod and optimism, prepare for disappointment. Most of Montana’s high-elevation lakes don’t shed their ice until late June or early July, and some hold onto it even longer. Lower-level lakes (6,000-7,000 feet) might be fishable by late May. Regardless, once the ice does melt off, that’s when the fish—fresh out of winter starvation—go on a feeding spree.
Montana’s high-elevation lakes don’t shed their ice until late June or early July, and some hold onto it even longer.
What’s for Dinner?
Good dry flies include parachute Adams, elk-hair caddis, beetles, and ants. Wind-blown terrestrials are a staple of alpine lakes, and you’ll have the best chances with a dry in the morning or evenings. Midday winds can also create prime terrestrial fishing conditions, as gusts deposit beetles, ants, and other unlucky bugs onto the water. As always, look for fish that are rising.
Typical nymph offerings include pheasant tails, midges, and hare’s ears in sizes 12-16. Whether suspended under a dry fly or fished under an indicator, they’re a solid bet. As with a river, pay attention to any bug life you see on the shore and select flies accordingly.
If you feel the urge to fish streamers, woolly buggers and leeches in olive and black are all you need. Find a wind-blown shoreline, cast into the chop, strip toward shore, and wait for a trout to grab the fly.
Other Considerations
Fishing mountain lakes is an exercise in both preparation and humility. The best ones aren’t easy to reach. Maps, apps, and local fly shops can point you to promising waters, but don’t rely on a fly-shop employee’s vague hand-wave toward somewhere up that drainage—do your homework.
Bring a small, lightweight fly rod (9-foot, 4- or 5-weight) with a floating line.
If it’s your first foray into backcountry fishing, go with someone who’s done it before. Check the weather, pack extra clothing, and tell someone where you’re going. And remember: bear spray is a necessity.
Fishing alpine lakes takes some faith. You hike in, sweat-soaked and slightly delirious from the altitude, believing—trusting—that something will be waiting for you beneath the surface. Maybe it’s a trout that hasn’t seen a fly in weeks, or months, or ever. Or maybe it’s nothing but the quiet of solitude.
Either way, the mountains don’t care. They were here before you, they’ll be here long after you, and they will stand witness as you reel in your fish or absolutely nothing at all. But that, more often than not, is reason enough to make the climb again.
Cameron Evans is a writer, angler, and conservationist based in Montana. When she’s not chasing trout with a fly rod, she’s telling stories about the wild places and public waters that make it all possible.
