Big Sky Anglers Weekly Fishing Report – 9/8/2022

by | Sep 8, 2022

Hello from West Yellowstone, Montana
– The Trout Capital of the World –

The Dog Days of Summer have stretched into the first week of September this year with smokey skies and hot temps making us all look forward to Autumn in Big Sky Country. However, it looks like a change is coming over the next few days. We anticipate this shift every September as it ushers in an exciting transition period between Summer and Fall.

For the next few weeks we could expect to see anything from terrestrial fishing with Hoppers and Ants on warm, sunny days to head hunting during fall mayfly hatches, and streamer fishing on colder, scuzzier days. More so than at any other time of the season, it’s critical to pay close attention to the weather forecast, and plan your fishing days accordingly.

It’s very common for a warm, windy day that produced great hopper fishing to be followed by a cold, scuzzy day that pumps out thick emergences of fall mayflies like Baetis or Mahogany Duns. Being prepared for all conditions and fishing opportunities is the key to success this time of year.

A reminder to everyone that our annual Trout Spey Days event is scheduled for September 9th and 10th, and is sure to be a good time as always. Lots to learn this year from our great lineup of presenters that includes Simon Gawesworth, Eric Neufeld, Lee Davison, George Cook, and Matt Klara. Head over to the event website via THIS LINK to get all the details. The presentation schedule was modified this past week to best take advantage of our time at the river. Call us at the shop to get signed up. Spots are filling up!

If you haven’t already, now is the time of the year to start planning your fall fishing trips to West Yellowstone, Montana. Give the shop a call or shoot us an email, we’d love to help you plan your trip or suggest some flies to tie up for September and October. If you haven’t walked in the fly shop this season, take a walk downstairs the next time around and check out the new fly tying section of the store. We have filled the Travel Lounge with tying materials and if you are in need of a place to tie some flies, there is table, light and vice waiting for you.

For the freshest report, be sure to stop by the shop at 39 Madison Ave in West Yellowstone where you’re sure to find a few sun-burned trout bums, bleary-eyed from fishing the previous night’s hatch well into dark, and plum full of more good info and passion than any other staff around. While you’re there, don’t miss our newly expanded fly tying lounge in the basement. You just might catch Hoovie or one of our other bug-obsessed fly winders at the vise answering fishing’s great mysteries with fur, feather, and thread.

Big Sky Anglers is OPEN from 7 am to 9 pm seven days a week.

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,

The BSA Crew

Weather Outlook 
The autumnal equinox may not be for a couple more weeks, but the annual battle between Summer and Winter that we call Autumn in Big Sky Country will begin in earnest this coming week. After a hot, dry stretch of weather with above average temps, we’re entering a period of cooler days with high temps ranging from the low-sixties to mid-seventies, and nighttime lows below freezing. By this time next week, if forecasts hold true, we could see our first significant shot of moisture for the fall season and a continued shift to cooler weather. Be sure to keep a close eye on the forecast, and give us a shout, or better yet swing by the shop if you ever need help deciphering the weather and planning your fishing accordingly.

Henry’s Fork River by Jonathan Heames

Island Park Dam: 930 cfs

Ashton Dam: 1480 cfs

St. Anthony: 1230 cfs

Fall River: 324 cfs

The Henry’s Fork has been holding up pretty well here lately, flows are at a good level and clarity has greatly improved over this past month. We can expect flows to remain relatively constant for this next week with a slow reduction in the weeks to come as water is moved downstream through the system from Island Park Reservoir to American Falls. There is good game to be found for those who look for it. Keep an eye on the forecast to help direct your daily movements.

Box Canyon: At just over 900 cfs, the Box Canyon is at a comfortable flow, easily read and fun to fish. Indicator nymphing rigs still dominate anglers’ tackle in here, but don’t be afraid to throw a streamer or dry/dropper if that’s not working. Weeds are something we all have to deal with here, sometimes you’ll have to choose a lighter rig to keep you above the weed beds and fish water that is an appropriate depth for the rig you’ve selected. The current flows allow for trout to be distributed throughout the canyon and in many of the smaller, less obvious slots, there are days when efforts are best spent in this water type. For flies, we’re finding success with small rubberlegs #10-12, perdigons #16-18 (Spanish Bullets, Bullet Quills, Jake’s Soft Hackle, and Napoleon Reds), PTs, Rednecks, small caddis pupa, as well as red and brown zebra midges will all do the trick here. Remember that trout don’t always move far for their food, especially when fishing smaller flies, so be ready with a hookset at the slightest indication of a change in indicator movement.

Railroad Ranch: Ranch anglers are returning with reports across the board, but we are generally finding good fishing in the morning hours until around 1 or 2pm. Some days are more sparse than others and require more walking to find reliable targets, but they’re around for those who persevere in their search. Drifting weeds can be a bit obnoxious in the afternoons, but this is par for the course this time of year. Learning to deal with weeds is an important part of fishing the Ranch in September, try to learn to shake the majority of them from your fly with a short, sharp back cast rather than having to bring your flies to hand after every drift. This will make you a more efficient angler and enable you to stay on target. Small spinners are the most regular morning menu item, both tricos and pseudos #18-20, but many of these fish can be taken on a slightly larger spinner or even a terrestrial pattern if your first presentation is clean and on target. Mahogany duns are the next big thing on the menu and are just beginning to show, we expect to see a few more of these around as the weather shakes up and cools down a bit this coming week. A well-stocked box for this week’s endeavors will include trico and pseudo spinners, mahogany duns and emergers #14-16, Honey Ants #14-16, small black ants #18-20, grasshoppers #6-12, small PMD emergers #16-18, as well as callibaetis spinners #14-16.

Canyon Country: The canyons of the Henry’s Fork remain a great place to enjoy some solitude and will usually provide a good day’s fishing for those that fast-paced water. Short casts with dry/dropper rigs are standard fare down here, but we are always prepared with streamers when we want to look for a larger fish or two. Remember that these sections above and below Mesa Falls are good places for a raft and good oarsmanship.

Warm River to Ashton: As we enter the post-Labor Day timeframe, this section above Ashton Reservoir will continue to produce good days of fishing with action on smaller to medium sized fish. We should start to see a reduction in the numbers of pleasure floaters down here as the weather cools and school is back in session. Browns are beginning to move around, it’s always worth spending half of this float trying to be creative with a streamer or a larger nymph to entice a brown trout to your line.

Below Ashton Reservoir: September is the month that things begin to liven up again down here, usually more reliably after the middle of the month, but a cold snap or cloudy day can present some opportunity for those looking to revisit these sections earlier. Dry/dropper rigs and streamers are the equipment of choice, small dry flies when targets reveal themselves. Even though our mornings can be quite cold around here, if the day is hot and sunny, things will slow down midday this week, so be prepared with a plan B for the afternoon.

Have fun out there!

Madison River by Dinah DiMeolo

Over the past week on the Madison we said goodbye to prime summer fishing, and after several days of abnormally hot weather, we can finally see the light at the end of the tunnel. While fishing has been somewhat inconsistent as of late between the float and wade sections of the Madison, there are still plenty of good days ahead yet this fall.

Flows dropped about 200 CFS this week, and with water temps finally starting to remain under 70 degrees on a daily basis this is a great sign moving forward. The forecast for this upcoming week is looking to drop into the mid 60’s and low 70’s, which should really give us some great opportunities at happy fish, as well as change things up a bit relative to bug life.

Given the curveballs we were thrown last week with a handful of super hot days, I would change things up a bit moving forward. If you’ve been fishing hopper droppers like it’s your job, I would take advantage of the next few colder mornings and start tying on some small streamers to throw along any slow water you can find. Bouface Leeches, small Sculpin patterns, or A BFE can likely get the job done stripping along any deep pockets or along an undercut bank. Any deep water you can find in the earlier hours of the day just might have a fish sitting and waiting for a hefty snack. Once you reach the heat of the day, nymphs will likely be your best bet until we hit the next few fall hatches. Olive Perdigons, Rednecks, Copper Duracells, and Hot-Spot Phesant Tails (#14-18) have been some recent productive nymphs. Keep an eye out for flying ants or other terrestrials that may still be roaming around as well.

As time goes by each of the next few days, I would take a minute to notice your surroundings before immediately switching your rig. Do you see a lot of hoppers? Are there fish feeding that you can see but maybe your nymph just isn’t deep enough? Are there any minor adjustments you can make before trying something completely new? Often times when things get frustrating and fish don’t seem to be cooperating (especially this time of year), being extra keen on your surroundings can often help you assess what to improve upon in order to hook into some fish.

Otherwise, enjoy the next few weeks of cooler weather, and now is your chance to come and enjoy a much quieter, less crowded trip to West Yellowstone!

Yellowstone National Park by Patrick Johnson

Though we’ve made it to September, late-summer weather conditions remain a heavy influence on our fishing successes in the Park. While we still have to remain vigilant about water levels and temperature when deciding where to fish on the western-edge of the park nearest the shop (Madison/Gibbon/Firehole rivers), it does seem like we just may be over the hump here pretty soon. Last week, temps reached the high 80s and low 90s, and the effect on fishing was definitely felt on most of the Park’s waters, with the bite slowing down drastically around 2pm. Luckily, our forecast for the coming days calls for cooler temps overall and even some precipitation and storms thrown in. Add in these brisk evenings and early mornings to the mix, and we should see things liven up here pretty soon.

At the risk of sounding like a broken record, our local “trout menu” remains largely unchanged – grasshoppers, beetles and ants are still the name of the game, with perhaps more emphasis placed on ants (in my experience). Everyone loves throwing those big, juicy, foam-bodied hopper patterns and watching a trout savagely attack their terrestrial, but now is the time we start seeing a lot of refusals. In my mind, those fish have simply seen so many hopper patterns at this point that the sight of our big splashy presentations can sometimes send them running for cover. Recently, Ant patterns have been a day-saver for me when targeting these selective fish – either fished solo, or trailing 12-16 inches behind a larger dry. We’ve got plenty of tricky ant patterns here in the shop, but my favorites have been Arrick’s Flying ant in cinnamon/black, Hoovie’s Crippled Ant, Jojo’s ant in red/black, and the always-effective Royal Wulff Cripple.

As I mentioned last week, early birds have been getting the worm with these recent frigid overnight temps – many of our resident streamer junkies and spey-freaks have been rewarded with some great early-morning fish caught both on the swing and while stripping streamers. Though it still feels like we’re a ways away from the iconic fall fishing conditions we know and love, I’d encourage all you early-risers to get out there and knock the rust off your strip set in the coming days – even if the Jury’s still out on their existence, you may just be rewarded with the mythical “early runner” or “pre-spawner” if you get out there at the crack of dawn.

Stay up to date on YNP roads below


The Lakes by Matt Klara

We’ve been seeing some great fishing on Hebgen Lake lately. Callibaetis hatches have been strong, with good spinner falls, and finally the trout are in “gulper” mode, patterning their rises. When the trout are putting only two and three rises together in sequence and then disappearing, we are still dropping a nymph below a dry fly or stripping a nymph across the target zone. When they are linking up their rises and staying near the surface, it’s time to go to a spinner pattern, they’ll often shun the nymph at this point of the hatch, usually around late morning or early afternoon.

As this summer weather continues, the lakes in this region will continue to fish well with callibaetis, damselflies, and terrestrial patterns. We are now expeiencing more consistent flying honey ants (#14) on the water as well. Any time you find these guys, there are trout eating them, so don’t be caught without the right fly!

If you find yourself out there with no surface activity, remember that it’s hard to go wrong with a chironomid and a general nymph fished static, or a slow stripped leech or callibaetis nymph.

The backcountry and higher elevation alpine lakes are very much still in play, though some of the aquatic insect activity is really beginning to drop off. Once that happens, look for terrestrials during the warmest parts of the day and otherwise fish subsurface with leeches, scuds, and dragonfly nymphs that have multi-year life cycles and will trigger a trout’s urge to feed. Up in the alpine, September means that winter is coming.

Regardless of where you are fishing, be aware of water temps. Lake fish are particularly susceptible to C&R mortality if temps climb and dissolved oxygen levels drop.

River Flows and the Weather Forecast
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