Runoff Report and Summer/Fall Streamflow Forecast and Fishing Outlook for Late May, 2021

Posted on May 31st, 2021 in Area Fishing News, Season Forecasts, Weather & Water Conditions

Introduction

Winter snowpack and how this snow melts from April through June are the primary drivers of summer water conditions: whether the water’s high or low, whether it’s warm or cold, etc. This in turn drives the fishing. In general, we like to see slightly above-normal snowpack since this leads to cool water and aggressive fish.

The lower the snowpack and hotter and drier the summer weather, the more likely we will have tough or limited fishing on late summer afternoons due to warm water. In exceptionally hot/dry years, we may even have stream closures in core watersheds in our operations area. Some watersheds are now always closed from 2:00PM to midnight in late July and August, though none of these are important fisheries at this time.

Winter and Early Spring Weather Summary

Winter started with a bang in early October, with over a foot of snow and below-zero temperatures even in Livingston. Things then got dry by early November and stayed that way through January. The early part of winter was so dry that Bridger Bowl Ski Area had to delay its opening until almost Christmas.

February really saved our bacon. The whole month was very cold and very wet. In fact the ski area set its record for February snowfall. This heavy snowfall propelled Yellowstone and Montana snowpack to above normal levels in most river drainages by mid-February. Those that didn’t jump above average climbed over the 95th percentile, close enough.

March returned to slightly warm and slightly dry conditions for most of the month, with a few cold and wet outbreaks. Snowpack increased in a general sense, but declined against average.

April turned out to be highly variable, despite a forecast that predicted warm and dry. We’d go from a couple days of light snowfall that mostly melted by noon (here in the low country) to bright sun and 65 degrees a day later. The last few days of April were exceptionally warm, with temperatures in Livingston reaching the mid-80s on the 30th. This prompted an early start to the snowmelt.

May was highly variable, with weather yo-yoing from hot and dry to cold and wet. We had accumulating snowfall that stuck around for a couple days here in Livingston as recently as May 20. June 5 it is forecast to hit 90 degrees. That’s how the spring has gone. On balance, May was probably a bit drier than normal.

Current Yellowstone and Montana Snowpack and Runoff Update

Current snowpack ranges from 38% to 129% of normal in the Yellowstone Country Fly Fishing areas of operation. Runoff is well underway everywhere, which is a big reason why these numbers are so variable. The other big factor is a heavy winter storm that mostly impacted central and northern Montana ten days ago. Basically, high mountains and especially high mountains north of here still have good snowpack. Otherwise, the snow’s almost gone.

Snowpack is 75% of normal in the  Upper Yellowstone Basin in Wyoming, basically meaning the Yellowstone River and all its tributaries upstream of Gardiner, Montana. This comprises all the core summer water within Yellowstone Park. The Upper Yellowstone Basin in Montana is at 77% of normal. This includes the Yellowstone Basin (including the Wyoming water) downstream to the Clark Fork confluence near Billings, Montana, at the eastern edge of YCFF’s operations area and beyond the Parks Fly Shop operations area.

Besides the above basins, which are the most important river drainages for both businesses, snowpack ranges from 38% of normal in the Madison-Gallatin Basin in YNP to  129% of normal in the Smith-Judith-Musselshell Basin, which barely touches on our operations area.

In general, snowpack is low to very low across the important drainages in our operations area. With above normal temperatures in the forecast, things will not improve.

General Expectations for Summer

Based on current Montana snowpack and predictions for June we expect the following for the core June-early September season. Conditions after mid-September depend on fall rain and snowfall:

  • A short runoff cycle that will end in all but the highest drainages by June 20.
  • Below-normal stream levels from this writing onward.
  • Above-normal water temperatures in all river basins between July 10 and August 15-20
  • More 2:00PM fishing closures than usual between the above dates.
  • Potential for poor fishing conditions after 2:00-3:00 during hot spells on many fisheries that do not meet closure criteria (note: Montana closes trout fisheries from 2:00-midnight when they touch 73 degrees three consecutive days to avoid stressing trout; above 70 is poor fishing anyway)
  • Potential for round-the-clock fishing closures in a few low-elevation fisheries (note: these are unimportant fisheries to most anglers in midsummer)
  • Spookier than normal fish in late July, August, and September
  • More fires than usual from late July through September

Water-Specific Predictions

This is the meat and potatoes for most visiting anglers. Here’s when we expect various important fisheries to blow out with runoff, clear from runoff, and how we expect they’ll fish through the summer. Within each jurisdiction, waters are discussed in approximate order of when they’ll leave spring runoff.

Montana Fisheries

Private Lakes: The private lakes are now enjoying their best fishing of the year. Given the hot weather forecast for the upcoming week, we anticipate some lakes will begin slowing down by mid-June this year. All lakes will be poor from the beginning of July through mid-September.

Missouri River – Land of Giants: Very low flows have led to crowded and so-so fishing on the Missouri so far this season. Weeds will be heavy in July and August due to the low flows, which will probably prevent us from fishing here July-September.

Area Reservoirs: Like the private lakes, the reservoirs are at their best right now and will likely begin falling off into summer doldrums with the upcoming heat wave. High-elevations reservoirs like Hyalite near Bozeman and Hebgen near West Yellowstone are a very different matter and should be fine except on hot/bright/windy afternoons in July and early August.

Madison River (Lower): The Lower Madison is at or near its best fishing of the year, though it’s very low. Caddis pupae, Yellow Sallies, and crayfish are working, and PMD might also be on tap. Forecast high temps will do this water no favors, though it probably won’t be too warm to fish before about June 20-25. The Lower Madison is always closed to fishing from 2:00PM until midnight from July 15-August 15. In reality it ought to be June 25 through Labor Day this year.

Jefferson River: The “Jeff” is now blown with spring runoff until about June 10. High air temps and low flows do this low-elevation river no favors. We might not have ANY fishable window between the end of the runoff and the onset of high water temps. Expect 24-hour closures here in late July and August, with 2pm to midnight closures in early July.

Boulder River: The Boulder has just gone into its heavy runoff, but it will drop quickly too. We expect marginal fishability by June 15. It’s very likely going to be an exceptionally short float season on the Boulder this year, with flows falling under the 500cfs threshold by July 15 to 20 at the latest. Expect low flows and stressed fish in late July and August, so no wade-fishing downstream of Natural Bridge in late summer, either. 2:00PM closures are possible in August from Natural Bridge to the Yellowstone.

Stillwater River: The heavy runoff has now hit on the Stillwater. Points upstream from the Rosebud confluence should come into shape June 15-20. Downstream, around July 1. Prime floating flows will be from June 20-25 through early August depending on the stretch. The upper Stillwater above the Rosebud will get too low by August 1. The lower Stillwater will likely get too low to float sometime between August 20 and Labor Day unless good late summer moisture occurs to keep things up. High water temperatures below the Rosebud confluence are likely in early August, with 2:00 closures possible but unlikely. More likely, you’ll just want to launch early and take off by 3:00 during hot spells.

Yellowstone River: The Yellowstone will experience maximum runoff around June 4 this year, with flows forecast to peak around 14,000cfs at the Corwin Springs gauge.. This is 6,000cfs below normal. Because of the low peak, expect fishable flows by June 20 at the absolute latest, with June 15 very possible. The most consistent fishing will range from June 25 to early August depending on the section and the weather. Late July and August will see water temperatures over 70 degrees on many hot afternoons. 2:00 closures are possible on the entire Yellowstone outside YNP but are most likely east of Livingston. Regardless of any mandatory closures, lots of days will demand “early-on, early-off” for good fishing, especially the week either side of the beginning of August when maximum sun/heat combine with lower flows. We expect many of our guided trips to meet by 6:30AM and be off the water around 3:00 during this period regardless of legalities. Mandatory 24-hour closures are unlikely anywhere on the Yellowstone, but are possible east of Livingston and especially east of Big Timber.

The Salmonfly hatch on the Yellowstone will almost certainly be fishable this year, though it will probably be of short duration. Look for the hatch from June 20 through July 4 depending on June weather and the specific stretch of river.

Most Small Streams: Except for a couple low-elevation odds and ends that fish well from mid-June until early July, like the Musselshell River and upper Smith River, most small streams will begin coming into shape in the first week of July and be best between mid-July and Labor Day. Most run ice-cold, which makes them excellent bets in late July and August on afternoons when big rivers may be too warm.

Yellowstone Park Fisheries

The Yellowstone Park fishing season opened May 29. Most “westside” fisheries are clear and fishable already, with the Firehole already probably at its best fishing level and temperature of the year. Crowds have been overwhelming, though. The rest of the park will become fishable between June 10 and July 1, depending on the water. The upper Yellowstone and a few other odds and ends do not open until July 15. Check regs to be sure!

Please note that fall fishing is really not discussed here. Most or all of the larger rivers in YNP become good again after September 1 when cooler nights allow water temps to drop.

Firehole River: The Firehole is low, clear, warm, and crowded. The extreme lower Firehole has already hit 70 degree water temps right above its confluence with the Gibbon, though most of the river is still in the high 50s or low 60s. The best fishing of the “early” season is already occurring on the Firehole. It will get too low and warm for good afternoon fishing by June 10 and maybe June 5. It will get too low and warm period around June 20 absent cool and wet weather. Yellowstone Country Fly Fishing does not expect to run ANY trips on the Firehole this spring due to the short cool-water window. If 24-hour closures are not instituted on the Firehole in July and August due to high water temps, shame on Yellowstone Park.

Madison River in YNP: The Maddy in YNP is clear and fishable and will be best before June 20. It will be too warm on bright afternoons thereafter and too warm period between July 1 and late August. Closures should but probably won’t be instituted from July 4 through August 15-20.

Gibbon River in YNP: The Lower Gibbon below Gibbon Meadows is low enough and clear enough now and will be best from June 1 through June 15. It will gradually get too warm thereafter and be too warm in July and August. From Norris Geyser Basin through Gibbon Meadows is in shape now and will be best from June 10 to June 20 and too warm between July 4 and Labor Day. From Virginia Cascade to Norris will drop into shape around June 10 and be best in July and early August. Upstream of Virginia Cascades is still undergoing grayling and westslope cutthroat restoration so is not recommended this year. 2:00 closures are likely and warranted below Norris Geyser Basin in late July and August.

YNP Lakes: All Yellowstone Park lakes that are open are accessible and fishable. Blacktail doesn’t open until July 1 and will likely already be too warm. Yellowstone Lake will be best before June 20. Cascade and Grebe will be best June 10 through early July.

YNP Central Plateau Streams: Streams like Nez Perce will drop into shape around June 10 and be best in late June and July.

Gardner River: Given the warm weather forecast, we don’t anticipate any “runoff breaks” on the Gardner. That said, it’ll be nymphable for good below Boiling River around June 10 and good by June 15. Osprey Falls to Boiling River will be a week later due to colder water. Above Osprey Falls will come in June 20 to July 1 depending on section and will be best in July. Below Boiling River will be too warm in the afternoons and may see closures in late July and August. The park is often overzealous with lower Gardner closures and may shut things down from Osprey Falls on down if they institute any closures at all. Closures between Osprey and Boiling River are NEVER warranted since this water stays below 65 all summer long no matter the weather.

Yellowstone River: The Yellowstone River above the falls always opens July 15 and will be best for the first two weeks. From the falls to the Lamar (Grand Canyon) will begin coming into shape around June 10-15 and be best from the point it’s barely fishable until about July 20 and again after September 15. It will be cool enough all summer, but can see heavy pressure in easy-access areas in late July and August. In the Black Canyon from the Lamar to Gardiner, it will track similarly to the Yellowstone outside the park as described above, except the Salmonflies will be present primarily in the first half of July and there’s less likelihood it’ll get too warm after 2:00 on late summer afternoons. Closures are unlikely on the Yellowstone inside YNP, though if the park institutes any closures at all they tend to go hog-wild with them.

Lamar, Soda Butte, and Slough Creek: Rough stretches of Slough and the Lamar will start coming in around June 20. Meadow stretches will come in around June 25 to July 1. The fishing will be best in July and on August mornings, though fishing will be good on cloudy afternoons even through August. We anticipate OVERWHELMING crowds on roadside easy-access portions of these streams this year. We’re talking people every 25 yards. This is due to the pent-up demand from people who didn’t travel last year combined with people who still can’t travel to more exotic locations overseas as well as low water that concentrates people in the main channels rather than allowing them to spread out in side channels. Closures are possible but unlikely in late July and August, though as noted the park can go bananas when they do institute closures (most recently 2007).

Rough Small Streams: As usual, small streams draining areas other than the park’s central plateau are steeper and rougher than others. They will come in around July 1 and be best from July 10 through mid-August.

Montana and YNP Summer Streamflow and Fishing Forecast for Early May 2021

Posted on May 2nd, 2021 in Season Forecasts, Weather & Water Conditions

Introduction

Winter snowpack and how this snow melts from April through June are the primary drivers of summer water conditions: whether the water’s high or low, whether it’s warm or cold, etc. This in turn drives the fishing. In general, we like to see slightly above-normal snowpack since this leads to cool water and aggressive fish.

The lower the snowpack and hotter and drier the summer weather, the more likely we will have tough or limited fishing on late summer afternoons due to warm water. In exceptionally hot/dry years, we may even have stream closures in core watersheds in our operations area. Some watersheds are now always closed from 2:00PM to midnight in late July and August, though none of these are important fisheries at this time.

Winter and Early Spring Weather Summary

Winter started with a bang in early October, with over a foot of snow and below-zero temperatures even in Livingston. Things then got dry by early November and stayed that way through January. The early part of winter was so dry that Bridger Bowl Ski Area had to delay its opening until almost Christmas.

February really saved our bacon. The whole month was very cold and very wet. In fact the ski area set its record for February snowfall. This heavy snowfall propelled Yellowstone and Montana snowpack to above normal levels in most river drainages by mid-February. Those that didn’t jump above average climbed over the 95th percentile, close enough.

March returned to slightly warm and slightly dry conditions for most of the month, with a few cold and wet outbreaks. Snowpack increased in a general sense, but declined against average.

April turned out to be highly variable, despite a forecast that predicted warm and dry. We’d go from a couple days of light snowfall that mostly melted by noon (here in the low country) to bright sun and 65 degrees a day later. The last few days of April were exceptionally warm, with temperatures in Livingston reaching the mid-80s on the 30th. This prompted an early start to the snowmelt.

Today things have cooled back down into the 50s at low elevation and are forecast to remain there through the middle of the week (today is Sunday). After a brief warmup to around 70 degrees, it’ll be back into the 50s again for most of the first half of May. The 6-10 and 8-14 day NOAA outlooks are both calling for a very high likelihood of below normal temps and above normal precip through May 15.

Current Yellowstone and Montana Snowpack

Current snowpack ranges from 71% to 91% of normal in the Yellowstone Country Fly Fishing areas of operation. This is a 10+ point drop for most basins just in the past 5 days, due to the sharp warmup. Most of April, snowpack remained where it had been in our last update, in the 85-97% range, though the latest round of snow around April 20 actually bumped things to 100% in one drainage.

Snowpack is 85% of normal in the  Upper Yellowstone Basin in Wyoming, basically meaning the Yellowstone River and all its tributaries upstream of Gardiner, Montana. This comprises all the core summer water within Yellowstone Park. The Upper Yellowstone Basin in Montana is at 87% of normal. This includes the Yellowstone Basin (including the Wyoming water) downstream to the Clark Fork confluence near Billings, Montana, at the eastern edge of YCFF’s operations area and beyond the Parks Fly Shop operations area.

Besides the above basins, which are the most important river drainages for both businesses, snowpack ranges from 71% of normal in the Jefferson Basin to  91% of normal in the Gallatin Basin. The worst snowpack is in the Jefferson Basin, which isn’t very important to us, but it’s not much better in the Madison Basin inside YNP, at 77% of normal.

Snowpack decline should level off through the first half of May provided we don’t get much warm rain at high elevations. In fact, it’s very possible snowpack numbers (as a percentage of average) will increase, particularly if the second week of May is as cool as the forecast says. It should be cool enough to snow at high elevations. I wouldn’t be surprised to see numbers increase 5-10% by mid-May except in those basins that are already under 80% of normal, since they’re lower elevation and already melting furiously enough they’re just going to blow.

Here’s a map showing Montana snowpack. The YCFF area of operations is circled in red. The Parks’ Fly Shop ops area is about 2/3 the size.

may 02 2021 snowpack in montana

General Expectations for Summer

Based on current Montana snowpack and predictions for spring weather, we expect the following for the core June-early September season. Conditions after mid-September depend on fall rain and snowfall:

  • An early beginning to the spring snowmelt, with a pause in mid-May that should bring an extended early “runoff window” on all area rivers
  • An early end to the spring snowmelt
  • Below-normal stream levels after July 1
  • Above-normal water temperatures in all river basins between July 15-20 and August 15-20
  • More 2:00PM fishing closures than usual between the above dates.
  • Potential for poor fishing conditions after 2:00-3:00 during hot spells on many fisheries that do not meet closure criteria (note: Montana closes trout fisheries from 2:00-midnight when they touch 73 degrees three consecutive days to avoid stressing trout; above 70 is poor fishing anyway)
  • Potential for round-the-clock fishing closures in a few low-elevation fisheries (note: these are unimportant fisheries to most anglers in midsummer)
  • Spookier than normal fish in late July, August, and September

Water-Specific Predictions

This is the meat and potatoes for most visiting anglers. Here’s when we expect various important fisheries to blow out with runoff, clear from runoff, and how we expect they’ll fish through the summer. Within each jurisdiction, waters are discussed in approximate order of when they’ll leave spring runoff.

Montana Fisheries

Private Lakes: The private lakes are now ice-free and fishable. As usual, they will be best from late April through mid-June (Story Lakes) or mid-July (Burns Lake). We are looking to add the Sitz Ranch Lakes to our repertoire. They are best before early July.

Missouri River – Land of Giants: Holter Reservoir is ice-free so jet boat trips are now available through Thanksgiving. The only limiting factor from here out is wind (N winds of 20+ mph are extremely dangerous). Due to low flows from the dam upstream, we expect things to get weedy by early July and be pretty tough in August and early September. Otherwise, this is a dependable fishery regardless of weather. Very low flows have thus far made things so-so at “LoG.”

Area Reservoirs: All low-elevation reservoirs are now ice-free. Wind permitting, we’ll be fishing some of those around White Sulphur Springs (there are four) this week. As usual, the best fishing is from ice-out through June on the low-elevation reservoirs near us.

Madison River (Lower): The Lower Madison is a perfectly reasonable fishery through the winter, though it’s best in May and early June. Due to expected low flows, the Lower Maddy may get questionable by June 20-25 this year. It now always has “hoot owl” 2:00PM to midnight restrictions from July 15 through August 15. These may be expanded to 24-hour closures this year if summer is hot.

Jefferson River: The “Jeff” is now blown with spring runoff, maybe through mid-June. The fishable window thereafter will depend on how fast it gets hot. Expect 2:00 closures after July 4, possibly expanding to a 24-hour closure from mid-July through August.

Boulder River: The Boulder has gone from 200cfs, less than half “floatable” flow, to 1200cfs in three days. 1200 is ideal floating level, but with a rise that fast it will probably be muddy. Once flows drop a hair early this week due to the cooldown, the Boulder will be an excellent choice until at least May 15, and probably more like May 20 before blowing again. Thereafter it will be muddy most of the time until about June 20. Note the “most of the time.” Unique among float rivers that ever get too muddy (the Lower Madison and Missouri never get too muddy to fish), the Boulder often drops into fishable shape for 2-3 days at a time even during the middle of the spring runoff. All it takes is a couple cold days. When these “runoff windows” occur, fishing is usually fantastic. The Boulder will drop from runoff for good around June 20. It will get too low to float by July 20 this year, and maybe as soon as the 15th. The headwaters will be fine to wade fish all summer, though the lower river may get low and warm enough that fishing after 2:00PM is not a good idea. This will be most likely the last week of July and first half of August.

Stillwater River: Upstream of the Rosebud confluence, the Stillwater tracks similarly to the Boulder in terms of entering and leaving runoff, as well as its floatable levels and late July and early August water temps. Downstream of the Rosebud, it’ll clear up around July 1 or perhaps a few days later. It should remain high enough to float until August 25. After that will depend on summer precip. High water temps suggesting a 2:00 quitting time are likely on hot days in August downstream of the Rosebud, though the Stillwater almost never gets statutory closures.

Yellowstone River: The Yellowstone in Montana has entered the early stages of spring runoff fast and hard, rising from under 2000cfs on April 27 to 6360cfs right now. It will drop into fishable shape sometime this week and stay there until May 15-20 if the forecast cool weather comes past. Thereafter, the river will remain in runoff for about a month except for the possibility of one or two runoff windows as described above for the Boulder. The Yellowstone will begin leaving runoff between June 20 and 25. The stretch from Gardiner to Yankee Jim Canyon and Carbella to Mallard’s Rest drops into shape first. Yankee Jim Canyon and points through and east of Livingston need another 10 days to two weeks to drop to safe levels (for us, 6000cfs on the Corwin Springs Gauge). The most consistent streamflows will be in July. The last week of July and the first three weeks of August may be too warm in late afternoon on a day-to-day basis from Gardiner to Livingston between July 20 and August 20, but 2:00 closures are unlikely unless runoff starts exceptionally early AND summer is very hot. East of Livingston, mandatory 2:00 closures are possible in the same timeframe and a lot of afternoons will be too warm on a day-to-day basis. Basically if it’s hot, bright, and dry, expect to take out early east of Livingston.

The Salmonfly hatch on the Yellowstone will almost certainly be fishable this year. Expect them beginning as the river drops out in late June through July 4, but probably not much or any thereafter. Ants will likely be better terrestrials this year. Terrestrial season is likely to start July 20 this year (early).

Most Small Streams: Except for a couple low-elevation odds and ends that fish well in late June, like the Musselshell River and upper Smith River, most small streams will begin coming into shape in the second week of July and be best between mid-July and Labor Day. Most run ice-cold, which makes them excellent bets in late July and August on afternoons when big rivers may be too warm.

Yellowstone Park Fisheries

Note: The Yellowstone Park season opens May 29 this year, as late as it possibly can. The season always opens at sunrise the Saturday of Memorial Day Weekend. Because of the late opener, we expect all of the early season fisheries to be ready on the opener, which is unusual. On the other hand, the late opener means that the Yellowstone from the falls to the Lamar (Grand Canyon), Slough Creek, and the Gardner River are almost certainly going to be muddy. In years with early openers, these waters can be fishable for opening weekend before they enter runoff.

Firehole River: The Firehole will be clear enough and fishable on the opener and be best before June 15. It may be too warm on bright afternoons thereafter and will almost certainly be too warm after noon no later than June 25, and possibly by June 20. The park has apparently stopped closing geothermally-heated waters like the Firehole when water temps get too high, as they always do in July and August, but the Firehole should be closed to all fishing in July and August downstream of Old Faithful this year, even if it isn’t. Above Old Faithful is a fine mountain creek in high summer, since it has little geyser water.

Madison River in YNP: The Madison will be clear enough and fishable on the opener and best before June 25. It will be too warm on bright afternoons thereafter and too warm period between July 4 and late August. Closures should but probably won’t be instituted from July 4 through August 15-20.

Gibbon River in YNP: The Lower Gibbon below Gibbon Meadows will be low and clear enough on the opener and best from June 5 through June 20. It will gradually get too warm thereafter and be too warm in July and August. From Norris Geyser Basin through Gibbon Meadows will drop into shape June 5-10 and be best through June and too warm between July 4 and Labor Day. From Virginia Cascade to Norris will drop into shape around June 20 and be best in July and August. Upstream of Virginia Cascades is still undergoing grayling and westslope cutthroat restoration so is not recommended this year.

YNP Lakes: Yellowstone Lake will be fishable out of the gate more than likely. Cascade, Grebe, and other small lakes in the central part of the park may be reachable on the opener but will almost certainly be ready by June 5. These lakes will be best in June and early July. Note that Blacktail Ponds opens in early July. It will likely be too warm already by then this year.

YNP Central Plateau Streams: Streams like Nez Perce will drop into shape around June 15-20 and be best before early August.

Gardner River: Occasional runoff breaks are possible before June 20 downstream of Boiling River, but it will drop into shape for real downstream of the High Bridge June 20-25 with the Salmonfly hatch thereafter downstream of Boiling River. The Salmonflies will last until July 20 in Sheepeater Canyon. The river below Boiling River will be too warm after 2:00 and maybe in general between July 20 and early September. Osprey Falls to Boiling River will be fine but likely crowded in easy-access areas all summer. The upper river (brookie water) will come into shape around July 1 and be best before August 15.

Yellowstone River: The Yellowstone River above the falls always opens July 15. From the falls to the Lamar (Grand Canyon) will begin coming into shape around June 15 and be best from the point it’s barely fishable until about July 20 and again after September 15. It will be cool enough all summer, but can see heavy pressure in easy-access areas in late July and August. In the Black Canyon from the Lamar to Gardiner, it will track similarly to the Yellowstone outside the park as described above, except the Salmonflies will be present primarily in the first half of July and there’s less likelihood it’ll get too warm on late summer afternoons.

Lamar, Soda Butte, and Slough Creek: Rough stretches of Slough and the Lamar will start coming in around June 25. Meadow stretches will come in around July 1. The fishing will be best before mid-August with low but not warm water conditions thereafter. We anticipate OVERWHELMING crowds on roadside easy-access portions of these streams this year. We’re talking people every 25 yards. This is due to the pent-up demand from people who didn’t travel last year combined with people who still can’t travel to more exotic locations overseas.

Rough Small Streams: As usual, small streams draining areas other than the park’s central plateau are steeper and rougher than others. They will come in around July 1 and be best from July 15 through August.

YNP and Montana Snowpack Update and Summer Streamflow and Fishing Conditions Predictions

Posted on April 2nd, 2021 in Season Forecasts, Weather & Water Conditions

Introduction

Winter snowpack and how this snow melts from April through June are the primary drivers of summer water conditions: whether the water’s high or low, whether it’s warm or cold, etc. This in turn drives the fishing. In general, we like to see slightly above-normal snowpack since this leads to cool water and aggressive fish.

The lower the snowpack and hotter and drier the summer weather, the more likely we will have tough or limited fishing on late summer afternoons due to warm water. In exceptionally hot/dry years, we may even have stream closures in core watersheds in our operations area. Some watersheds are now always closed from 2:00PM to midnight in late July and August, though none of these are important fisheries at this time.

Winter Weather Summary

Winter started with a bang in early October, with over a foot of snow and below-zero temperatures even in Livingston. Things then got dry by early November and stayed that way through January. The early part of winter was so dry that Bridger Bowl Ski Area had to delay its opening until almost Christmas.

February really saved our bacon. The whole month was very cold and very wet. In fact the ski area set its record for February snowfall. This heavy snowfall propelled Yellowstone and Montana snowpack to above normal levels in most river drainages by mid-February. Those that didn’t jump above average climbed over the 95th percentile, close enough.

March returned to slightly warm and slightly dry conditions for most of the month, with a few cold and wet outbreaks. Snowpack increased in a general sense, but declined against average.

April and the remainder of spring are forecast to be warmer and drier than normal.

Current Yellowstone and Montana Snowpack

Current snowpack ranges from 88% to 103% of normal in the Parks’ Fly Shop and Yellowstone Country Fly Fishing areas of operation.

The highest snowpack is 103% of normal in the Upper Yellowstone Basin in Wyoming, basically meaning the Yellowstone River and all its tributaries upstream of Gardiner, Montana. This comprises all the core summer water within Yellowstone Park. The Upper Yellowstone Basin in Montana is at 102% of normal. This includes the Yellowstone Basin (including the Wyoming water) downstream to the Clark Fork confluence near Billings, Montana, at the eastern edge of YCFF’s operations area and beyond the PFS operations area.

Besides the above basins, which are the most important river drainages for both businesses, snowpack is not so good. It ranges from 88% to 94% of normal and falling fast due to current warm temps (forecast to touch 70 degrees in Bozeman and Helena this weekend). The worst snowpack is in the Madison Basin, at 88% to 89% of normal. This includes the Firehole River in Yellowstone Park.

In general, snowpack is on the decline as a percentage of average everywhere due to current warmer-than-normal weather. In lower-elevation basins like the Madison within YNP, it may have peaked in general already, several weeks early. Despite the current warm spell, it is unlikely than snowpack has peaked in higher elevation drainages in gross terms, though it will probably continue to decline against average through spring, due to the forecast warm/dry weather.

Here’s a map. Our operations are is outlined in red (approximately).

early april montana snowpack update

General Expectations for Summer

Based on current Montana snowpack and predictions for spring weather, we expect the following for the core June-early September season. Conditions after mid-September depend on fall rain and snowfall:

  • Below-normal snowpack on May 1, flirting with far below normal (80% or less of average) in a few basins.
  • An early beginning to the spring snowmelt
  • An early end to the spring snowmelt
  • Below-normal stream levels after July 1
  • Above-normal water temperatures in all river basins between July 15-20 and August 15-20
  • More 2:00PM fishing closures than usual between the above dates.
  • Potential for poor fishing conditions after 2:00-3:00 during hot spells on many fisheries that do not meet closure criteria (note: Montana closes trout fisheries from 2:00-midnight when they touch 73 degrees three consecutive days to avoid stressing trout; above 70 is poor fishing anyway)
  • Potential for round-the-clock fishing closures in a few low-elevation fisheries (note: these are unimportant fisheries to most anglers in midsummer)
  • Spookier than normal fish in late July, August, and September

Water-Specific Predictions

This is the meat and potatoes for most visiting anglers. Here’s when we expect various important fisheries to blow out with runoff, clear from runoff, and how we expect they’ll fish through the summer. Within each jurisdiction, waters are discussed in approximate order of when they’ll leave spring runoff.

Montana Fisheries

Private Lakes: The private lakes are now ice-free and fishable. As usual, they will be best from late April through mid-June (Story Lakes) or mid-July (Burns Lake). We are looking to add the Sitz Ranch Lakes to our repertoire. They are best before early July.

Missouri River – Land of Giants: Holter Reservoir is ice-free so jet boat trips are now available through Thanksgiving. The only limiting factor from here out is wind (N winds of 20+ mph are extremely dangerous). Due to low flows from the dam upstream, we expect things to get weedy by early July and be pretty tough in August and early September. Otherwise, this is a dependable fishery regardless of weather.

Area Reservoirs: Some (Dailey) are already ice-free. All the rest will lose their ice by early May. As usual, the best fishing is from ice-out through June on the low-elevation reservoirs near us. We’re looking forward to putting the jet boat on many reservoirs by late this month.

Madison River (Lower): The Lower Madison is a perfectly reasonable fishery through the winter, though it’s best in May and early June. Due to expected low flows, the Lower Maddy may get questionable by June 20-25 this year. It now always has “hoot owl” 2:00PM to midnight restrictions from July 15 through August 15. These may be expanded to 24-hou closures this year if summer is hot.

Jefferson River: The “Jeff” will blow out with spring runoff between April 20 and the end of April and stay muddy until about June 15. The fishable window thereafter will depend on how fast it gets hot. Expect 2:00 closures after July 4, possibly expanding to a 24-hour closure from mid-July through August.

Boulder River: The Boulder is rising now, but will not be floatable before April 20 to the end of April. It will blow out with runoff between May and May 15 and stay muddy most of the time for a month to six weeks. Note the “most of the time.” Unique among float rivers that ever get too muddy (the Lower Madison and Missouri never get too muddy to fish), the Boulder often drops into fishable shape for 2-3 days at a time even during the middle of the spring runoff. All it takes is a couple cold days. When these “runoff windows” occur, fishing is usually fantastic. The Boulder will drop from runoff for good sometime in the last 10 days of June, probably early in that period. It will get too low to float by July 20 this year, and maybe sooner. The headwaters will be fine to wade fish all summer, though the lower river may get low and warm enough that fishing after 2:00PM is not a good idea. This will be most likely the last week of July and first half of August.

Stillwater River: Upstream of the Rosebud confluence, the Stillwater tracks similarly to the Boulder in terms of entering and leaving runoff, as well as its floatable levels and late July and early August water temps. Downstream of the Rosebud, it’ll clear up around July 1 or perhaps a few days later. It should remain high enough to float until August 25. After that will depend on summer precip. High water temps suggesting a 2:00 quitting time are likely in August downstream of the Rosebud.

Yellowstone River: The Yellowstone in Montana will enter runoff sometime in the last 3-4 days of April or first week of May, depending on how warm temps are after April 20. It will remain in runoff for about six weeks except for the possibility of one or two runoff windows as described above for the Boulder. The Yellowstone will begin leaving runoff between June 20 and 25. The stretch from Gardiner to Yankee Jim Canyon and Carbella to Mallard’s Rest drops into shape first. Yankee Jim Canyon and points through and east of Livingston need another 10 days to two weeks to drop to safe levels (for us, 6000cfs on the Corwin Springs Gauge). The most consistent streamflows will be in July. The last week of July and the first three weeks of August may be too warm on a day-to-day basis from Gardiner to Livingston between July 20 and August 20, but 2:00 closures are unlikely unless runoff starts exceptionally early AND summer is very hot. East of Livingston, 2:00 closures are possible in the same timeframe and a lot of afternoons will be too warm on a day-to-day basis. Basically if it’s hot, bright, and dry, expect to take out early east of Livingston.

The Salmonfly hatch on the Yellowstone will almost certainly be fishable this year. Expect them beginning as the river drops out in late June through July 4, but probably not much or any thereafter. Ants will likely be better terrestrials this year. Terrestrial season is likely to start July 20 this year (early).

Rosebud Creek and Forks: We’ll be fishing the Rosebud and its forks for the first time this year, in cooperation with Quaking Aspen Ranch. It is great in the latter half of April and first part of May before blowing out around May 10. It typically stays muddy until about July 1. It remains a good wade-fishery until mid-November. The mainstem is floatable for a month to six weeks after dropping into shape, exclusively through a partnership with Quaking Aspen. Note that public access is limited on this water. Quaking Aspen has 1.5mi exclusive and about 4mi with friendly neighbors.

Most Small Streams: Except for a couple low-elevation odds and ends that fish well in late June, like the Musselshell River and upper Smith River, most small streams will begin coming into shape in the second week of July and be best between mid-July and Labor Day. Most run ice-cold, which makes them excellent bets in late July and August on afternoons when big rivers may be too warm.

Yellowstone Park Fisheries

Note: The Yellowstone Park season opens May 29 this year, as late as it possibly can. The season always opens at sunrise the Saturday of Memorial Day Weekend. Because of the late opener, we expect all of the early season fisheries to be ready on the opener, which is unusual. On the other hand, the late opener means that the Yellowstone from the falls to the Lamar (Grand Canyon), Slough Creek, and the Gardner River are almost certainly going to be muddy. In years with early openers, these waters can be fishable for opening weekend before they enter runoff.

Firehole River: The Firehole will be clear enough and fishable on the opener and be best before June 15. It may be too warm on bright afternoons thereafter and will almost certainly be too warm after noon no later than June 25, and possibly by June 20. The park has apparently stopped closing geothermally-heated waters like the Firehole, but the Firehole should be closed to all fishing in July and August downstream of Old Faithful this year, even if it isn’t. Above Old Faithful is a fine mountain creek in high summer, since it has little geyser water.

Madison River in YNP: The Madison will be clear enough and fishable on the opener and best before June 25. It will be too warm on bright afternoons thereafter and too warm period between July 4 and late August. Closures should but probably won’t be instituted from July 4 through August 15-20.

Gibbon River in YNP: The Lower Gibbon below Gibbon Meadows will be low and clear enough on the opener and best from June 5 through June 20. It will gradually get too warm thereafter and be too warm in July and August. From Norris Geyser Basin through Gibbon Meadows will drop into shape June 5-10 and be best through June and too warm between July 4 and Labor Day. From Virginia Cascade to Norris will drop into shape around June 20 and be best in July and August. Upstream of Virginia Cascades is still undergoing grayling and westslope cutthroat restoration so is not recommended this year.

YNP Lakes: Yellowstone Lake will be fishable out of the gate more than likely. Cascade, Grebe, and other small lakes in the central part of the park may be reachable on the opener but will almost certainly be ready by June 5. These lakes will be best in June and early July. Note that Blacktail Ponds opens in early July. It will likely be too warm already by then this year.

YNP Central Plateau Streams: Streams like Nez Perce will drop into shape around June 15-20 and be best before early August.

Gardner River: Occasional runoff breaks are possible before June 20 downstream of Boiling River, but it will drop into shape for real downstream of the High Bridge June 20-25 with the Salmonfly hatch thereafter downstream of Boiling River. The Salmonflies will last until July 20 in Sheepeater Canyon. The river below Boiling River will be too warm after 2:00 and maybe in general between July 20 and early September. Osprey Falls to Boiling River will be fine but likely crowded in easy-access areas all summer. The upper river (brookie water) will come into shape around July 1 and be best before August 15.

Yellowstone River: The Yellowstone River above the falls always opens July 15. From the falls to the Lamar (Grand Canyon) will begin coming into shape around June 15 and be best from the point it’s barely fishable until about July 20 and again after September 15. It will be cool enough all summer, but can see heavy pressure in easy-access areas in late July and August. In the Black Canyon from the Lamar to Gardiner, it will track similarly to the Yellowstone outside the park as described above, except the Salmonflies will be present primarily in the first half of July and there’s less likelihood it’ll get too warm on late summer afternoons.

Lamar, Soda Butte, and Slough Creek: Rough stretches of Slough and the Lamar will start coming in around June 25. Meadow stretches will come in around July 1. The fishing will be best before mid-August with low but not warm water conditions thereafter. We anticipate OVERWHELMING crowds on roadside easy-access portions of these streams this year. We’re talking people every 25 yards. This is due to the pent-up demand from people who didn’t travel last year combined with people who still can’t travel to more exotic locations overseas.

Rough Small Streams: As usual, small streams draining areas other than the park’s central plateau are steeper and rougher than others. They will come in around July 1 and be best from July 15 through August.

2021 Winter Snowpack Update and Summer Fishing Forecast

Posted on March 6th, 2021 in Area Fishing News, Season Forecasts

Intro

Winter is now 3/4 over here in Yellowstone Country, which means we have a fair idea of what summer streamflows are going to look like. If you aren’t familiar with the Western water year, we get most of our summer streamflow from snowpack. High snowpack that melts late and we have high water. Low snowpack that melts early, low water.

All in all, we like snowpack to sit around 110% of normal when it starts melting in late April. This gives us a slightly late start on summer waters like the Yellowstone, Lamar, Boulder, and Stillwater, but also gives us a cushion of higher, colder water if late summer is hot and dry.

Lower snowpack than this makes it more likely we’ll have low, warm water in late summer, with the potential for closures or at least tough late-afternoon fishing in early August. Higher snowpack than 110% means a very late start on summer rivers, though usually excellent fishing from late July onward.

The Winter So Far

Winter started in early October, with heavy snowfall and cold weather. Then the script flipped from November through January. During this period, we had far warmer and drier conditions than normal, which led to extremely low snowpack and the prospects for a dangerous drought. If you believe it, we had heavier snowfalls and colder temperatures here in Livingston in October than in January.

The script flipped again at the beginning of February. All of February was cold and wet in the region, which dramatically increased snowpack throughout the region and moved us largely out of the danger zone (for now). The first few days of March have been very warm and dry, though it is supposed to cool off and get wet again over the next week.

Current Conditions

Here’s a map covering “west-wide” snowpack. Green and pale blue are good. Yellow and especially orange and red are bad. The northwestern corner of Wyoming and southern Montana are the drainage basins that impact our waters. As you can see, southwest Montana and Yellowstone are in pretty good shape compared to many areas in the West, especially points south of us.

westwide snowpack March 6 2021

This graph updated daily can be accessed at this link.

Narrowing our focus a bit, here’s Montana, with little extensions showing basins in NW Wyoming that impact our operations. Our approximate operations area is outlined in the medium red line.

Montana snowpack for Mar 6 2021

Access versions of this graph updated most days at this link.

To interpret the above numbers, snowpack within our operations area ranges from 90% to 108% of normal. The most important basins, the Upper Yellowstone in Wyoming and upper Yellowstone in Montana, are at 108% and 106%, respectively. So far so good. We wouldn’t mind if things were a bit higher, but we were 20 points lower six weeks ago.

We are definitely not out of the woods yet, though. We’ve still got about six weeks to build or lose snowpack before the normal spring melt begins.

Outlooks for the Next Three Months

March, April, and May weather will govern whether the decent numbers above translate to summer. This crystal ball is unclear. This graph is updated on the third Thursday of every month. It predicts an equal chance of above and below normal temps and above and below normal precip for March through May. So no help there.

Shorter-term outlooks for March are more pessimistic and predict below normal precip. Going off the short-term weather forecast and these outlooks, that’s honestly what I expect, too.

Summer Streamflow Conditions Outlook

Taking all of the above into account, here’s what I believe we’re looking at as of right now:

  • Below normal to near-normal snowpack and likely summer water conditions: February is the only reason we’ll even be near-normal, but the long-range outlooks suggest things will stay flat or decline slightly through the spring until the real melt hits.
  • Warm water temps in the last week of July and first half of August, but no closures of note: While we don’t have enough snowpack to guarantee cool water and frisky fish through summer, we should have enough to prevent any drought-related closures in all of the important summer basins, basically meaning all of the Yellowstone drainage. The lower Jefferson, lower Madison, and some other dribs and drabs are likely to have 2:00PM closures in late July and August (the Madison always does), but these aren’t places we fish at that time, anyway.

Most specific predictions will have to wait another six to eight weeks, when we know for sure what our snowpack looks like and whether or not the heavy melt has started drastically early.

The one thing I do feel pretty confident in stating is that the Firehole River is going to get too warm by June 20-25 this year. With only a 91% snowpack in its basin at the moment, it is very unlikely it will climb to average. Basically, as soon as it really gets hot and sunny in mid-late June, that’ll be it for the Firehole. If you’re a Firehole fanatic, I suggest coming before June 20. The YNP season opener this year is May 29.