Big sky anglers weekly fishing report – 7/15/2021

by | Jul 15, 2021 | 0 comments

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Smokey skies are here to stay for the long haul, so it seems. The good news is that the smoke filters out the direct sunshine and fish are digging it. Mid July shifts our mind to Yellowstone National Park and the squiggly blue lines that remain nameless. Strap on a pack, grab your bear spray, water bottle and take a walk. Find a small stream and take your 3wt for a walk! The Madison and Henry’s Fork remain solid options this week as well, no doubt. We are in for another week of hot and dry weather both here in the Hebgen Basin and the Madison Valley, don’t expect much for rain this week but one never knows so keep that rain jacket close by.

Big Sky Anglers is OPEN from 7am to 9pm seven days a week. Our fly shop remains a clean and healthy environment for both our customers and staff members. Stop on by, say hello, and we’ll get you taken care of. Most importantly, stay safe, stay healthy, and enjoy your time outside.

Take care and fish on,
~ Joe, Justin, Jonathan, and the BSA Crew


Island Park Dam:   1450 cfs

Ashton Dam:   2940 cfs

St. Anthony:   1040cfs

Falls River at Chester: 154 cfs

Stable flows and high water have been the norm on the Henry’s Fork this week, this is keeping the fish happy and healthy and has given us lots of opportunity at some great trout fishing. These hot and dry days are keeping irrigation demand high, lots of water moving through the system to water the fields in the upper Snake River basin.

In the upper river, the Box Canyon is rolling along at a high but healthy flow, keeping the trout willing and in good shape for sporty fishing. The water is still a bit off color but the fishing remains solid, giving many anglers a memorable day’s fishing in a spectacular setting. Nymph rigs are the norm here, most days we are starting with a BB split shot and adjusting the weight from there. The reports are in from Idaho Fish and Game (IDFG) and the box is host to a robust population of 12-15” rainbow trout this year as well as a very solid population in all of the up and coming age classes. This year’s report shows better populations of 15-18” fish than prior years as well. At this time of year, lots of approaches can yield results, ranging from the standby rigs of perdigons, PT nymphs, red and brown zebra midges to copper zonkers trailed by prince nymphs or your favorite and most trusted trailing nymph patterns. Dirty water lends itself to flies with hot spot collars and the sparing use of fluorescents as well as the old standards in your nymph boxes. Lots of floaters of all types are using the Box these July days, so be prepared to share the water with recreational floaters and other fishing folks.

The Railroad Ranch section has been fishing well but is a bit spotty these days. Good fishing generally is found in the upper reaches during the mornings and early afternoons. Evening fishing is a good bet as well, but the hot summer days without cloud cover call for an early dinner and a return to the water a couple of hours before sunset. Flav spinners are the bug to be on the lookout for, but anglers will also find opportunities with tan and olive caddis, sizes 16-18, some gray drake spinners, and pmds. The perfect day here is a calm and warm morning with lots of spinners, followed by a pmd hatch through the midday, and a thunderstorm-generated flav hatch in the afternoon. Seek the bugs and you will find the fish. The lower Ranch has been very spotty, but we are shifting to a period where the areas with spring influence will provide good sport. Be on the lookout for callibaetis spinners, flying ants, and grasshoppers as they will all be arriving on the scene here in the coming weeks.

Canyon country below the Ranch remains high but stable, those who are wishing to escape the crowds found in other parts of our area’s rivers can find solitude and lots of willing trout in fast-paced pocket water. Dry/dropper rigs are the norm here, but streamers are a good idea during a period of cloudy weather or afternoon thundershower.

The river below Ashton Reservoir is unusually high for this time of year, but these hot and sunny days take their toll. The heat of the afternoon is best avoided, but some opportunity can be found in the first half of the day as well as the evenings. Hatches are almost non-existent, so be on the lookout for opportunistic food sources like the odd golden stonefly, grasshoppers, ants, and small mayfly spinners. Nymph fishing will produce some results as well, but be sure to keep an eye on the thermometer, as the water approaches 70 degrees it is worth considering the health of our trout and moving on.

Good luck out there!


The high elevation fisheries of Yellowstone Park continue to be a terrific option during these hot, dry days.

Nighttime low temperatures have routinely been dropping down into the 30’s in the high country keeping water temps nice and cool. With another week of hot, dry weather in the forecast, cool water will continue to be a hot commodity.

Mid-July means it’s time to start thinking about the backcountry fisheries in YNP. Get off the beaten path, and go explore the 90% of Yellowstone that 90% of park visitors don’t see.


Fishing remains consistent in the Cutthroat Corner of the park. PMD’s and Caddis will make up the bulk of the bug activity in the coming week, but there is still a chance at seeing a Green Drake, or a Gray Drake Spinner. Hoppers, Beetles, Crickets, and ants are not to be forgotten as well.

Anglers have been suffering through a tougher than normal biting fly hatch in recent weeks. Luckily, the worst of the bugs seems to be behind us. Let’s keep our fingers crossed that it stays that way.

As always, keep a close eye on the forecast and flows as afternoon/evening thunderstorms can bump flows and muddy waters in some of our favorite fisheries in the Park. Follow the links at the bottom of the report to check flows, or better yet, give us a call or swing by the shop in West for up to the minute info.


The Gallatin River drains a large watershed high up in the southern Gallatin Range of Yellowstone Park. It’s waters are always the coldest in the area making for a great option during these especially warm days.

Late afternoon and evening fishing has been good with caddis emergences and mayfly spinner falls bringing fish to the surface well past sunset.


Today is opening day for the iconic section of this river upstream from Chittenden Bridge. This is among the best sight fishing venues in our sport, and it’s in prime condition this year for the opener. Expect to see Salmonflies, Golden Stones, PMD’s and Caddis with Gray and Green Drakes imminent.


This is a good time to look for Callibaetis spinner falls on any calm, warm mornings. The shallow weed flats near Bridge Bay, Gull Point, and Sand Point all provide opportunities for the wade fisherman to cast dry flies to cruising Cutts.


On July 10th the flows at Hebgen Dam were reduced by 100 cfs taking us to 1160 CFS up top and 1390 CFS at Varney Bridge. While these flows are great, there is something to keep in mind. Last week, the flows at Varney were 1690, so they dropped 300 in a week’s time. 100 of that came from the drop at Hebgen and the other 200 came from the drop in tributaries. The tribs help provide cold water and keep the river cooler. The other big news in the Madison Valley is the Goose Lake Fire which is burning south of $3 Bridge around Cliff and Wade Lakes. This fire will most likely burn all summer long and into the Fall; the powers that be are calling this a “long term event”. The fire is roughly 4000 acres and is pumping out smoke all day long. The good news is that the smoke provides a filter from the hot summer sunshine and has been helping to keep the river a bit cooler. The bad news…well…its smokey. River temps are fluctuating about ten degrees throughout the day and the fishing is hanging right in there.

Wade Stretch:
While Salmonflies are finished up, there are still a few Golden Stones hanging around with fish still giving a big hairy eyeball on fluffy dry flies. Yellow Sally stoneflies are around in decent numbers as well. PMDs and Caddis are where it’s at; these flows are fantastic and should allow for more high quality bank fishing in the weeks to come. There are millions of Epeorus spinners fluttering around so be sure to take those with you as well; a #16 and #14 Jojo’s Rusty will fool most trout. Cover water with those dry flies and keep moving until you find fish willing to rise. Slow down and concentrate on similar types of water as you move up stream. Nymphing with rubber legs, BH pheasant tails, golden stone nymphs, perdigons, prince nymphs, and crystal dips has been effective in the deeper runs.

Float Stretch:
The big key here is to get on early and run long floats. Our best advice is to stay away from the afternoon/evening floats and give those fish a break. The river temps are swinging 10 degrees throughout the day and by 4pm the Madison is getting pretty warm. Lyons to Ruby, Windy to Story or Ruby to Varney are all solid choices for those longer floats. Drop a tungsten bead head off a Chubby or a #12 Jojo’s Ant and fish with confidence. Caddis have been the main dry fly in the float stretch, but there are mayfly spinners throughout the river. Micro Chubbys will take their fair share if trout as well and if you find yourself wondering what else to toss out there, ants will be solid choice for the rest of season. Hoppers are clicking around so that should round out your fly selection. Nymphing from the boat is a great option as well with fish eating Hare’s ears, PT’s, Shop Vacs, various Perdigons.

Please be respectful to those fish that do eat your fly. Land them quickly and take care to revive each fish with your anchor on the bank. Trout pics are something we all enjoy, but if you can avoid it in the afternoons please do so. Get creative with your pics and keep those fish wet. Celebrate the trout in the net and enjoy watching them swim away. We find that a slow mo video is the best way to capture the moment!


This week the focus is on Hebgen. The lake is getting low as water continues to be released into the Madison, and there will definitely be times of day and places on the lake where water temps on the surface are too warm to fish ethically if you plan to Catch & Release, so use that thermometer, and fish smarter, not harder. That said, we have fully entered the window where gulper fishing is our primary focus on this local stillwater. Subsurface tactics will certainly be effective, especially during periods of heavy chironomid activity or when the wind puts the damper on the surface feeding activity. Callibaetis spinners, duns, emergers, and nymphs are the primary hatch matching patterns needed for the gulpers, but certainly don’t forget to pack some tricos and even some caddis patterns to round out your arsenal.

One of the trickiest parts of gulper fishing is figuring out which way the fish is moving, and how fast, so you know where to cast your fly. There are some days and some fish that will always make you feel like you are playing a rigged game of Whack-A-Mole, but there are some tricks you can apply to better your success. First, when you see a rise, try and look for heads, dorsal fins, and tails. That is a dead giveaway of direction. Then, notice the bow wave pushing out ahead of the fish. The next rise will almost never be inside of that bow wave, so be sure to cast out ahead. Ideally, the fish will rise again and again moving in the same direction. Judging that perfect fly placement in 2-dimensions is the hallmark of the experienced gulper angler. If you think your casts are perfect, but no fish are eating your fly, my experience suggests that you may actually be casting 1-3 feet short! It’s a trick of the eye, perhaps. Don’t be afraid to lengthen that shot as an experiment. Lastly, one of the best ways to increase your odds is to find fish that are cruising and rising along some sort of defining edge. Taking away one direction they can zig or zag adds to your odds. Edges formed by aquatic vegetation, surface chop, or even the shore can all play to your advantage.

For those looking to up their callibaetis game, navigate over to our blog and check out our posts about this high profile stilwater insect.



Below are links to the flows in Montana and Idaho as well as. This time of the year flows and the weather are changing daily, if not by the hour. Click the links below for the most up to date information.

Montana River Flows
Idaho River Flows
West Yellowstone Weather Forecast