Spring Runoff Update and Summer and Early Fall Streamflow and Fishing Forecast – Late May Update

Spring Runoff Update and Summer and Early Fall Streamflow and Fishing Forecast – Late May Update


Montana lifts its nonresident quarantine order on June 1. It becomes legal on that date for me (and all other guides/outfitters/shops) to take nonresidents who haven’t undergone the mandatory 14-day quarantine fishing. Speaking for probably every guide in Montana, I hope you consider booking some trips if your health and funds allow. I have taken out PPP loans, but for sole-proprietors like me, the amounts offered by these loans only cover a couple weeks of lost summer work, since they’re averaged over the entire year’s income rather than just the peak summer season.

Spring runoff is now heavy everywhere. Over the next month to six weeks, all area waters will drop out of the melt and fall into fishable shape.

Here’s the short version:

  • The spring runoff is now underway on all area rivers, including those with spring water components (Firehole) and which are resistant to a little bit of warm weather (Boulder). Even portions of the Missouri below Holter Dam were blown out last week.
  • Following a cool spell last weekend, complete with snow even at valley levels, it is now very warm and runoff is quite intense. Rivers are not safe to float even for whitewater purposes, due to woody debris and other obstructions.
  • Winter snowpack was quite high in most area drainage basins, but we’ve had an early start to the spring runoff which made snowpack in some low-elevation basins drop sharply, while in others it’s still holding steady at slightly above-normal levels.
  • A slight cooldown is forecast for mid-late June. I suspect this will be too late to “pause” remaining snowmelt but will really just result in area fisheries clearing a bit sooner due to a slight flattening of the curve (see what I did there?).
  • Most area “summer” fisheries will drop into shape between June 20 and July 10. Temperature-related problems and below-normal streamflows are likely in the Madison and Jefferson basins, but the Yellowstone basin (including the Lamar and Gardner Rivers in YNP and the Boulder and Stillwater Rivers north of YNP) should be near-normal.

Current Conditions

Runoff is very intense right now. High but fishable flows on the Yellowstone are around 10,000cfs. The river is at twice this level now and will probably rise still further. All flowing water in the region with the exception of the Firehole River and the lower Madison River between Ennis Dam and Cherry Creek are too high and/or muddy to fish right now. In a week or so, the Gibbon and Madison within Yellowstone Park will fall into shape, along with the rest of the lower Madison. There’s a good chance the upper Madison will become marginally fishable as well.

This means lakes are the best bet now and for the next ten days or so. Both private ranch lakes and warm-water opportunities in the region are good choices now. I went fishing on a moderate-sized reservoir in eastern Montana for a few days and did fair, though the warmth pushed the pike deep and after the first day I lost the school of good-sized eater crappie I’d been chasing. Here’s the best bass I caught, on a five-weight and a crappie fly, of all things.


eastern Montana largemouth bass
Eastern Montana largemouth bass.

Coronavirus and Guiding in 2020 – Reopening the Big Sky

Two big changes to the reopening plan I cover in my previous post are important for visiting anglers:

  1. Montana is moving to Phase II of its coronavirus reopening plan on June 1. In a change to this plan, out-of-state tourism restrictions are now being lifted in Phase II rather than Phase III. In other words, as of June 1 there’s no more out-of-state quarantine and I can legally take you fishing.
  2. In conjunction with the change in Montana’s tourism rules, Yellowstone Park is opening its northeast, north, northwest, and west entrances, in addition to all roads in the park not otherwise closed for construction. The park’s 100% open as of June 1, in other words.

The above changes mean that subject to common sense, social distancing requirements, and assuming no mass surges in coronavirus which shut things down again, the fishing and guiding seasons are about to restart again. Things won’t be “normal,” but at least they’ll exist…

Due to expected low crowds this season combined with good water conditions four years running, I anticipate very good fishing this year for those who make the trip.

Snowpack Update and What the Snowpack Says About Summer Conditions

We saw above normal snowfall and colder than normal temperatures from February through mid-April in Montana, with snowpack in the Yellowstone River drainage peaking at about 125% of normal as of my update in early April. This snow started melting early, around April 20, which ate into the snowpack numbers substantially, but the numbers stabilized and increased through the middle of May. Late May has returned to warm temperatures, near-record warm temperatures in some cases, and the snow is now melting furiously again. It will likely continue doing so for about 10 days before conditions return to cooler-than-normal temperatures.

Right now, basins within my operations area range from 81% of normal up to 112% of normal. The lowest snowpack numbers are found in the Madison River basin in Montana, while the highest number is found in the Upper Yellowstone Basin in Wyoming and Yellowstone National Park. The Yellowstone Basin in Montana (which factors in the Wyoming numbers as well) is at 107% of normal. All of these numbers will continue to decline sharply in the next few days.

Overall snowpack is thus winding up near average with a somewhat early runoff. I expect flows to be well below normal in the Madison Basin, though they will be near-normal in the Yellowstone Basin. I anticipate overall slightly early clearing dates in summer 2020. There is the possibility of tough fishing in late afternoon on a day-to-day basis in the last ten days of July and first half of August due to warm water temperatures, though this depends on weather. I do expect the lower Madison River to be too warm and low by about June 25 this year, whereas last year it fished well into July. The Firehole may well get too warm on a day-to-day basis by mid-June this year, especially in the afternoons. Even with massive amounts of snow runoff in the river, the Firehole is already hitting 68 degrees in the afternoons.

I do not anticipate any closures due to low streamflow or high water temperatures on any waters which are not always terrible in high summer (Jefferson, lower Madison, Firehole). The Yellowstone basin should all be fine except possibly too warm for good fishing some days between 3:00 and 7:00PM during the dog days. This will just mean getting started and finishing early.

Anticipated Dates Rivers Will Drop from Runoff and Expected Best Fishing Periods

This is the meat and potatoes for most readers.

Firehole River

The Firehole may be tea-stained on June 1 but should not be too dirty to fish again this season. It is already fishing for anglers coming up from the Wyoming entrances to the park. It should fish best in the first half of June this year, then decline for about a week, then be too warm even in the mornings by around June 25.

Gibbon River

The Gibbon is likely running too high and tea-brown for right now, but once flows drop by June 5 it will be good to go. It will fish best from this point until about June 20, then slowly decline until about July 4. After July 4, the waters below Norris Geyser Basin will be too warm except in the mornings. There is limited fishable water above Norris due to the continuing westslope cutthroat and grayling reintroduction project underway above Virginia Cascades, including Grebe and Wolf Lakes.

Madison River Inside YNP

The Madison inside the park is running high and hard right now. Expect streamers to be the best bet until June 5 or so, followed by PMD and caddis hatches. The best fishing on this section of the Madison for the “early” season as opposed to the fall season will be the middle two weeks of June. This stretch of the Madison will be too warm particularly in the afternoons by July 1.

Madison River “Between the Lakes”

The short section above the tributary creeks may be clear for now, but crowded. The creeks should clear up by about June 10, after which this will be a good stretch through the rest of the year.

Lower Madison River (Below Ennis Lake)

Running very high, which will hurt the dry fly bite even if bugs are hatching. Caddis, Yellow Sallies, and several mayflies are possible. San Juan Worms and crayfish are probably the best bets overall. Ready now, but will get better in early June as mud from Cherry Creek stops pouring in. Will likely get too warm by June 25 unless significant cool spells take over by then. The lower Madison is the best float river near me, and will be until the Boulder drops into shape.

Lakes in Yellowstone Park

Yellowstone Lake is fishable now and will be as good as it gets until late July for cutthroats or late June for lake trout. Lewis Lake is probably still ice-bound. Smaller lakes will be soggy wet hikes to access and will be high, but otherwise should be fishing right now and will be good choices until lake July.

Gardner River

The Gardner Below Boiling River is always fishable on a day-to-day basis with big nymphs from the normal park fishing season opener on the Saturday before Memorial Day onward. With the heavy runoff we’re seeing right now, the Gardner is definitely out until June 15 OR the next cool spell, whichever comes first. Salmonfly hatch the last week of June and first week of July, maybe even starting June 20 if conditions remain warm on balance for the next several weeks. After mid-July, may be touch and go particularly after lunch until the middle of September due to warm water temps. Day-to-day weather will govern this.

The Gardner from Osprey Falls to Boiling River is similar in structure to the Gardner below Boiling River (a hot spring), but much colder. Therefore it starts fishing later and remains good all summer and until the first extended cold snap in October. Portions remain good until the end of the season. This year, it should get going with nymphs around June 20-25 and be at its best in late July and the first half of August. The Salmonfly hatch will take place from around July 4 through July 20-25. The Gardner always has the longest-lasting Salmonfly hatch in the West, though the fish (6-13″ on average) are not as large as many other Salmonfly waters. Bigger fish hunting is always better from late August through fall.

Above Osprey Falls, the Gardner is a brook trout fishery (with a few small rainbows mixed in near the falls). It will be ready around July 4 and best from about July 15 through mid-August, as always. The upper river tributaries that come together near Indian Creek Campground always clear at least 10 days before the main river and are best from this point until late July. This is all beginner and kid water only.

Madison River (Quake Lake to Ennis Lake):

Very marginal right now due to mud from tributaries. Conditions will improve by mid-June. While the water will be cold enough all season, I wouldn’t be surprised to see very low flows here by August.

Jefferson River

Only good for about a week after it leaves runoff and again after September 1 or so. This year it will leave runoff around June 20.

Boulder River

During runoff the Boulder goes up and down like a yo-yo due to short-term weather conditions. Right now it’s totally blown (I looked at it yesterday). Safe flows are 2000cfs, and it’s at 4600 right now. It may hit record flows for the date tomorrow. The Boulder is running so high and hard that it’s very possible the next cold spell around June 10 will drop it into fishable shape for the season, especially from boats.

The float fishing on the Boulder in late June and early July should be spectacular this year, due to reduced guide traffic on this small river. I expect the Boulder to be at floatable levels of 2000 to 500cfs from whenever it clears until about July 20 this year.

Yellowstone River (Grand Canyon)

Always fishable before any other stretch of the Yellowstone due to the moderating influence of Yellowstone Lake upstream and the lack of large tribs between the lake and the Lamar confluence. Will be fishable with nymphs and streamers around June 20, or maybe even June 15. Salmonflies begin around June 25-July 1 in isolated areas and best the second week of July, but continue in isolated areas until about July 25. This water is good well into October provided you get on water that hasn’t already been fished on a given day. Tower Area may be less crowded this year due to roadwork between Tower Falls and Canyon (Tower Falls is accessible).

Stillwater River

Above the Rosebud should drop into shape around June 20-25 and be best for the first month or so, getting pretty low thereafter. Below the Rosebud, will come in around July 1 and be best in late July and August. The Stillwater should be very good this year due to reduced traffic, though the difference won’t be as pronounced as on the Boulder and Yellowstone, since more traffic here is local anyway.

Yellowstone River (Black Canyon and Gardiner to Pine Creek)

This includes both the walk-wade Black Canyon inside Yellowstone Park, which runs from the Lamar to the park boundary at Gardiner (and really for 2-3 miles or so below Gardner, since drift boats do not put in until a rough access at the 2mm or a better one at the 3mm), the “upper Yellowstone” float section from near Gardiner to Carbella, and most of Paradise Valley down almost to Livingston.

This water will drop into shape (except Yankee Jim Canyon) in the last ten days of June or the first few days of July. I suspect the last week of June for this. Flows need to be under 10,000cfs as measured at the Corwin Springs stream gauge. The Salmonfly hatch will begin at about the same time on the float stretch and last about a week there. The hatch will start a week later on the walk stretch and last until the last few days of July in a few areas near the Lamar confluence.

The best fishing of the season on this water will probably be in the latter half of July this year, due to low pressure during what is normally the highest-pressure period. I expect the best July and early August fishing on this portion of the Yellowstone of my career, subject of course to day-to-day weather. This is especially true of the float section which is often wall-to-wall boats in July but won’t be this year.

Fishing will remain good on this section through fall, though the deeper, faster sections are better once the water drops below about 3000cfs.

Yankee Jim Canyon will drop below 6000cfs (the level I consider safe to float in a raft) around July 10-15 and be at its best as always in late August and September.

Lamar River, Slough Creek, and Soda Butte Creek

This water will all come into shape sometime in the first week of July, with the best fishing in the latter half of July and first half of August. Thereafter, expect spookier and spookier fish requiring smaller and smaller flies, as always. Pressure should be reduced this year, but it will still be high relative to everything else.

Most Small Streams

A few small streams in the Yellowstone, Gardner, and Madison drainages that drain from lakes and/or hot spring basins will be fishable between June 10 and June 20 depending on the creek, but most small streams will truly drop into shape around July 15 and be best in August, as they always are.

Yellowstone River (Pine Creek to Laurel)

The rougher, bigger portion of the Yellowstone from Pine Creek down through Livingston and on east to Columbus and beyond is too high and rough for at least a week and often two weeks after most of the Yellowstone upstream. I expect it will drop into shape by July 15 this year and perhaps as early as the 10th. From Pine Creek to Mayor’s Landing in Livingston is pretty consistent from when it gets low enough right through the fall provided water temperatures remain below 70 degrees and above 47 or so. East of Mayor’s Landing is much more a “big fish hunting”
game. It is good but hard for the first ten days or two weeks after it clears, then less consistent but easier through August. By Labor Day things really depend on sticking a pig on a streamer or good hatches.

Pressure will be reduced on this stretch, particularly east of Livingston where there is more guide than local traffic, but this stretch of the Yellowstone is hard no matter what. It might just be less hard this year.

Water temps may be a problem on this stretch of the Yellowstone in August, particularly east of Livingston. If water temps are breaking 70 degrees, plan to fish 6AM to 2PM rather than in the afternoons and evenings.


There’s going to be good to great fishing this year, particularly in July and provided temps remain cool in August. We’re on year-four of decent to great water levels in most area basuns, which means we should see a large average size to the fish as well as some real monsters. This combines with low overall tourist traffic to mean the fish won’t be as picky as usual (read: they will be dumber than normal).

The Madison Basin will not be as good as the Yellowstone basin, due to lower flows.

If your finances and health make a trip feasible, I suggest coming, and I’d love to be your guide if you do…

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