Summer Streamflow & Fishing Forecast for Early April, 2024

Winter 2023-2024 has been warm and dry in Yellowstone Country, just like it has just about everywhere except California through Colorado. For a while we were flirting with record-low snowpack, and 50 degree days have been more common than below-zero here in Livingston. At the end of January we were expecting dire summer water (and fire) conditions. While February and March have generally been wet, and not as warm relative to average, we still anticipate a light runoff that ends early, followed by low water and difficult conditions in late summer. Cross your fingers for a late runoff and wet spring and early summer.

The above is basically the same as our previous update. That’s because things haven’t changed much. They have improved slightly, however.
Note that the maps we used to include on these posts are no longer produced. Instead, find them here: NWCC Maps.

Winter Weather Summary and Current Snowpack

We saw our heaviest snowstorm prior to late January in late October. That about sums things up. As of late January, we were sitting at roughly half to two-thirds of our normal snowpack, depending on location. Some areas of Montana were in even worse shape. We were expecting little to no spring melt and dire conditions possibly beginning as early as July 15.

Conditions have improved since then due to slightly above normal precip in February and March. The areas in the far southern parts of Yellowstone Park and even into Wyoming south of the park (the Yellowstone’s extreme headwaters) in particular saw significant increases.

As of March 31, snowpack in our operations area ranges from 66% in the Smith-Judith-Musselshell Basin at the northern edge of our operations area to 91% of normal in the Madison watershed inside YNP. Our most important basins, the Yellowstone in YNP and in Montana, are at 83% and 80%, respectively. Since we consider anything less than 80% as of May 1 a real problem indicating a strong likelihood of 2:00 hoot owl closures and potentially full fishing closures, we are not happy with where we stand, though the Yellowstone Basin in particular is heading the direction we want. It’s doing so too slowly to get to normal, but at least we’re no longer below 80% (for the moment).

Outlooks for Spring and Summer

Prospects for April through June (basically spring) are looking a bit better than they were when we posted our last update two weeks ago. The NOAA outlooks in February for March–May suggested warmer than normal spring conditions combined with equal chances of above and below normal precip. The new outlook is below. Chances for above-normal precip are better, and instead of being locked into strong chances of above-normal temperatures, we’re right on the edge of above normal vs “equal chances” (which I figure means “normal”) being favored. A normal to wet spring combined with normal-ish temperatures (particularly in May) would be ideal to improve late summer conditions.

Spring outlook:

The summer outlook is not as friendly. In fact this outlook is even worse than it was a couple weeks ago.

The only bright spot is that NOAA is now forecasting La Nina for next winter. The first year of a La Nina folloing a strong El Nino (which we had this past fall and winter, but which is not fading fast) is typically cold and wet to the northwest part of the continental USA, including Montana. We certainly hope so… In fact the hot/dry summer outlook is actually common for us in La Nina years. We like to see “LN” winters and springs, but “EN” summers as far as keeping temps in check and getting a little precip.

General Outlook for Summer Fishing

All of the above suggests we’re looking at a low snowpack running 75-85% of normal at the beginning of runoff, leading to an early end to runoff and low to extremely low water conditions for most of summer.

Because of this, we anticipate an early start to summer fishing on our most popular and important fisheries, with the best fishing running earlier to much earlier in the summer than normal. Late summer (July 20 through August) will see low water and difficult fishing condition, and 2:00 closures are likely in many areas. The first half of August in particular is likely to be grim, especially on float fisheries outside YNP where water temps slant warmer than higher in the mountains. Water conditions and fishing quality from late August through September will depend on prevailing weather conditions. Basically if we get some cooler, cloudy weather and/or early fall rains, the fishing will be good even with low water. If high sun and heat continue into mid-September or beyond, the fishing will be tough. That said, all complete fishing closures are likely to be lifted no later than August 25 and should be limited to minor fisheries (like the Lower Madison) if we avoid extreme summer heat. 2:00 closures will be lifted by August 25 elsewhere.

Detailed Predictions for Specific Watersheds

Fisheries are discussed first via jurisdiction (Montana vs YNP), then according to their expected end to the spring melt.

Montana Fisheries

Paradise Valley Spring Creeks: No runoff, and the best fishing will occur from now through April and again in late June and July, as usual. Almost all late June and July dates are already fully booked.

Lower Madison River: Slightly higher water in late May and June, but no unfishable runoff. Best fishing in late May and early June, with water temperatures rising over 70 degrees by June 20–25 and 2:00 closures basically certain in July and August. Full closures are likely in late July and early August.

Upper Madison River: Slightly higher water in late May and June, but no appreciable runoff except at most for a week in early June. Best fishing in June and early July. 2:00 closures are possible but unlikely in late July and August unless we see an extreme early warmup in June and early July.

Gallatin and East Gallatin Rivers: Unfishable runoff for 3 weeks or so starting in early May. Best fishing in late June and July on the mainstem Gallatin. Best fishing in late June and early July on the East. 2:00 closures are almost certain on the mainstem downstream from Hwy 84 near Four Corners and on the entire East beginning in late July. Full closures are likely in these areas in late July and August.

Jefferson River: Unfishable runoff for three weeks starting in early to mid-May. 2:00 closures certain and full closures are likely almost immediately thereafter.

Boulder River: Unfishable runoff for three to four weeks starting in mid-May, but there will be short windows of good fishing during this period whenever we see spells of cooler weather. The best fishing will occur during these spells of cool weather and for 2–3 weeks beginning in mid-June (for floating) and in July (for wading). The lower river will get too low to float sometime between July 4 and July 15, depending on the progress of the spring melt and early summer moisture. No closures are likely, but full closures really ought to be implemented on the lower Boulder for fish health after about July 20.

Yellowstone River: Unfishable runoff for 4–5 weeks beginning in late April (boo) to around May 10 (please, please, please). There will be fishable windows during the spring melt, which will peak much lower than normal at around 13,000 to 15,000 at Corwin Springs (20,000 is average). The best fishing will occur during these fishable windows as well as for a month beginning about a week after spring runoff recedes enough to make the river fishable. This great window will begin sometime between June 15 and June 25, probably around June 20. The fishing during this window is likely to be very good and also simply easier than usual, since the river is unlikely to be up fully in the bushes as usual. The Salmonfly hatch will begin about the same time and should be very good (albeit probably very fast-moving) due to anticipated low water. 2:00 closures are almost certain east of Livingston and likely everywhere from July 20 through August 20. Full closures are possible but unlikely except in the event of record heat and drought. Nonetheless, fishing in August and early September is going to be tough except in the roughest water and/or during cooler, cloudy weather. Overall, we anticipate the rough water near Gardiner will fish better than elsewhere in the mid-late season, particularly if you’re hoping to fish dry flies. The 20mi from Gardiner to Point of Rocks is likely the only stretch where we’ll be fishing dries regularly in August and the first half of September.

Stillwater River: Unfishable runoff for three to four weeks starting in mid-May, but there will be short windows of good fishing during this period whenever we see spells of cooler weather. The best fishing will occur between June 20 and July 20 on the upper river and from July 4 into early August on the lower river provided water temps do not get too high (this will depend on summer temps and precip). If we see a hot summer, 2:00 closures are likely downstream of Nye beginning in late July and extending into late August. The lower river will hopefully remain high enough to float through August, but unless we see high summer and early fall precip, this is not a year when we’ll able to float the Stillwater after Labor Day.

Creeks: Meadow streams like the upper Musselshell will be best in late June and too low/warm by mid-July. Mountain creeks will be best from July 4 until early August and will be trickles by late August.

Yellowstone Park Fisheries

All flowing water in YNP might see 2:00 closures in late July and August. We do not anticipate any full closures in the park, even though all water downstream of geyser basins should really be closed from sometime in the first half of July until Labor Day.

Lakes in YNP: Almost all should be accessible and ice-free on the opener and will fish best for the first month (assuming they are open; Blacktail Ponds opens in early July and will probably already be too warm).

Firehole and Upper Madison Rivers: Tannin-stained “brown” water will be present prior to June 5, but these will not see unfishable runoff. The best fishing will occur prior to June 20 on the Firehole and prior to June 25 on the Madison. Portions of the Firehole will see temp spikes over 70 degrees by June 20 and the Madison by July 1. They ought to close then, but probably won’t until the anticipated full 2:00 closure hits.

Gibbon River: No unfishable runoff downstream of Norris Geyser Basin. Above, the water will probably be too high and cold until between June 5 and June 10. The best fishing downstream of Norris will occur in the first half of June but will be okay until June 25. It will exceed 70 degrees thereafter and should be avoided. Above Norris, the best fishing will be in late June and July. The water will get very low but probably never over 70 degrees thereafter.

Yellowstone River (Grand Canyon): Will be high, difficult to wade, and murky but probably not unfishable for about two weeks at the beginning of the season. The fishing will be phenomenal with stonefly nymphs and streamers if you can handle the wading . Salmonflies after June 20 and best June 25 through July 10. The best fishing will fade by late July, but this water will remain comparatively high and cold throughout the season and should get low enough to wade completely across in places (we won’t say where) by Labor Day, so this will probably be the best August and early September fishery in the region for those up for the travel.

Gardner River: The Lower Gardner will have clear days and muddy days from the opening of the season (note that I am SPECIFICALLY not saying this will assuredly be the Saturday of Memorial Day Weekend as usual, because I have heard things I should not have heard) until about June 10, then be nymphable for about a week. All of this fishing is for strong waders only. Thereafter it will get slightly easier to wade and fish with dry-dropper combos. Salmonflies June 20 until July 20 depending on section. The area below Boiling River will get too warm by July 15 and stay that way until late September. The area between Osprey Falls and Boiling River will stay cool enough but probably be busy into early August, then get a lot harder though not impossible. The upper water near Indian Creek will drop and clear enough for your beginner fishing needs around June 25. It will fish best for the month thereafter.

Yellowstone River (Elsewhere): The upper river near and above Yellowstone Lake opens July 1 and will be best for the three weeks thereafter. Normally we suggest waiting here until July 15 to let the trout finish spawning, but because of the low water and warm winter, they ought to be done by July 1 this year. The flows will actually be relatively high here since the area feeding Yellowstone Lake is actually at near-normal snowpack, unlike everywhere else. The Black Canyon might see a few fishable windows in early June, but will really drop in around June 20 and be best for the month thereafter. Flows will be low and the fish spookier than normal in August and early September, but this water is tight enough and deep enough it will still fish okay if you get away from the crowds near Gardiner and Hellroaring (they can actually be awful near Gardiner now) and water temps stay under 70 degrees.

Lamar River System: Slough might be fishable with streamers around the opener before blowing out, if we have a cool spring. Realistically, all three major waters in this basin (Lamar, Soda Butte, Slough) will come in between June 20 and July 1 depending on when runoff begins and be best for the month thereafter. Late August and September will see very low water, very crowded conditions, and beat-up fish.

Creeks: Meadow streams will fall into shape around June 10 and be best from June 15 through July 15, except for those in the Gardner and Lamar systems which will come in between June 20 and July 1 and be best for the month after that. All will be trickles by early August. Rough mountain creeks will come in during late June and be best from around July 4 into early August, but will be trickles by late August.

Summary

We anticipate low to very low water and fair to poor conditions in August, but late June and early July will see much better fishing than usual, with many more clear opportunities (such as the Yellowstone in the Grand and Black Canyons) starting in June than usual. We suggest coming at least a couple weeks earlier in the season than usual, if you can, assuming you’re looking for your “usual” fishing conditions. We also suggest being adaptable in late July and August and fishing where water temps and flows are most conducive to good fishing, and using guide or shop-recommended tactics. If you insist on fishing hoppers in the middle of Paradise Valley in August, you will probably be disappointed.

Overall, we’ve seen a slight uptick in expected conditions during the peak June through September season, though it now seems very unlikely we’ll get close to normal as we were still hoping a few weeks ago. April is kind of the kicker month. Cool and wet and we’ll be in much better shape on May 1 than we are now. Warm and dry and we could be back to anticipating very poor conditions.

Our next full update will drop in mid-April. There’s a big storm forecast for late this week that could really help snowpack (if it’s cold enough) or really hurt. Hopefully we get lots of snow up high and rain only at low elevations.