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Category: Snowpack, Streamflow, and Summer Fishing Predictions

Updates on winter snowpack and likely summer streamflow and fishing conditions, mostly posted from January through June

Continued Improvement in 2021 Snowpack and Fishing Season Outlook

Continued Improvement in 2021 Snowpack and Fishing Season Outlook

Ten days back I posted about how I was holding off on posting about our current snowpack and what it means for the 2021 fishing season. I’m STILL not going to go into extreme detail because we’re STILL getting tons of snow.

The above is great news for the 2021 fishing season. Back at the beginning of January we were hurting, and January itself was dry, too. I was still on my “rock” snowboard on February 1 because not only were a few rocks still exposed at Bridger Bowl, there were also stumps, bushes, and clumps of grass, when all that junk is usually buried.

Simply put, we were looking at a drought season three weeks ago, with the possibility of widespread late afternoon fishing closures if summer turned out hot. Now we’re fast approaching exactly where we want to be for snowpack, which in turn bodes well for summer streamflow and fishing conditions.

A quick reminder before I lay out some numbers: most of our summer water comes from winter snow. Once runoff peaks in June, the water continually drops until sometime in September when fall rains usually raise things a swidge again for a few weeks before rivers drop to their winter low flows. High snowpack means a high peak runoff means higher flows and colder water temperature through summer means happier and healthier trout means much happier fishing guides and clients.

All in all, we like snowpack to be 100 to 115% of normal at the end of April. This sets us up for normal to slightly high streamflows no matter what happens for summer temperatures and rainfall.

It does mean our summer fisheries (Yellowstone, Boulder, and Stillwater Rivers for floating, northern YNP for wade-fishing) start in early July instead of late June, but it sets these fisheries up for much better conditions from about July 20 through mid-September. Anyway, we have plenty of other spring fishing options now that Walter is running power boat trips and we float the Lower Madison. These fishing options are great during the May to early July runoff season.

Here’s where the important drainage basins in our operations area stand as of Feb 17. They’re given in order of approximate importance to our operations:

  • Upper Yellowstone Basin Inside and Upstream of YNP: 109%
  • Upper Yellowstone Basin Downstream of YNP: 107%
  • Madison/Gallatin Basin Inside YNP: 90% 🙁
  • Madison Basin Outside YNP: 89% 🙁
  • Gallatin Outside YNP: 101%
  • Jefferson (Impacting the Missouri R.): 97%
  • Helena Valley (Missouri R.): 106%

As you can see from the above, we’re near or slightly above normal for two out of three of our critical basins. There’s definitely still some improvement needed in the Madison-Gallatin, especially for you Firehole fanatics.

Still, things have improved substantially of late, and we’re hoping they keep improving.

Early January Snowpack Report and VERY Early Summer Streamflow Predictions

Early January Snowpack Report and VERY Early Summer Streamflow Predictions


Note that this is a VERY preliminary report. Right now long-range outlooks are still calling for a wet winter, with heavy weather predicted for the Northern Rockies in the second half of this month that could completely change the picture below. We’ll gain a better and better understanding of what our snowpack and summer streamflows will look like as winter and early spring progress. By April 1 we’ll have a pretty clear picture of how much snow we’ll have. By May 1 we’ll know if it’s melting early. So take the following with a HUGE grain of salt. At this point there’s no reason to begin changing trip plans you’ve made for late July and August.

The Importance of Snowpack

Visitors from many parts of the country are used to fishing tailwater and spring-fed trout streams that do not depend on winter snows for their flows. Most of our waters are fed by surface drainage and limited amounts of groundwater. Both factors are driven by winter snowpack: how much snow falls and when it starts melting in the spring. High snowpack that melts late means we’ll have a late spring melt that lasts into July, but strong, cold flows through the hottest parts of summer. A low snowpack that melts early means we’ll have a spring melt that ends in mid-late June, and we’ll be sweating our streamflows and water temperatures in late July and August.

High snowpack years mean a delayed start to some of our top fisheries (like the Lamar River for a chief example), but good fishing and healthy fish afterwards. Low snowpack makes for great early summer fishing, but high water temperatures, stressed trout, and the related stream closures come late July and August.

Winter Snows so Far

We saw a cold and wet October, including 18″ of snow on the ground in one storm here in Livingston. November and December have been warm and very dry. The closest ski hill, Bridger Bowl, didn’t open until about December 20 and still only has 18 inches of snowbase. My “rock board” is getting a workout for sure.

Current snowpack ranges from a low of 64% of normal in the Madison Basin outside YNP to a high of 105% of normal in the Yellowstone Basin inside and upstream of Yellowstone Park. The Madison Basin is more accurate, since the Yellowstone Basin includes areas near the Teton Mountains 150 miles from here that have gotten far more snow than the Lamar and Gardner Basins and the canyon stretches of the Yellowstone inside YNP where we actually do most of our fishing. The Northeast Entrance snow sensor on the upper reaches of Soda Butte Creek tells this tale: it’s currently at 71% of normal snowpack.

Summer Streamflow Predictions

Simply put, snowpack sucks right now and we need more snow, or we’re going to have low, warm water, stream closures, and lots of fires in late summer.

If things continue as they are, runoff will begin to tail off starting around June 10 and be over on all waters by July 1. The best fishing on most of the waters in the northern part of YNP and north to Livingston and beyond will take place from about June 20 through mid-July, with late summer fishing utterly dependent on cool weather that keeps water temperatures below the 70-degree mark. The Firehole and Gibbon on the west side of Yellowstone Park may begin getting too warm by June 10, as they did in 2015-2016, our last low-snowpack years.

2:00PM stream closures are likely throughout our operations area due to warm water starting by July 20 and lasting for a month or so. The Yellowstone is usually resistant to such closures, but I wouldn’t be surprise if closures have to be instituted all the way upstream to Gardiner, or even in Yellowstone Park.

Again, the above assumes that current low snowfall continues. Hopefully when I make the next update in a few weeks, I’ll have a completely different report.

Runoff is Fading Fast! Final Streamflow & Summer Fishing Forecast

Runoff is Fading Fast! Final Streamflow & Summer Fishing Forecast

Walter posted his final runoff update and summer fishing forecast over at his website. Check it out.

In brief:

  • The spring runoff is still heavy on most freestone rivers across the northern part of Yellowstone Park and points north. It is basically over in the central and western parts of Yellowstone Park as well as west and northwest of the park. The Madison Basin in particular is now down to something like 30% of its normal snowpack for the date, meaning it’s game on over there.
  • Runoff came early and except for a couple short “runoff breaks,” was quite intense. Now that we’re past peak runoff, the cool spell coming this week will likely drop larger, low-elevation rivers out of the spring runoff to fishable levels for the season, though flows will still be high until about July 4.
  • Winter snowpack was quite high in most area drainage basins, but the early and heavy runoff has melted this snow fast. We now have below-normal snowpack everywhere, drastically below normal in the Madison Basin. This means we’re looking at below normal streamflows for July-September.
  • Area fisheries that are still in spring runoff will drop into play between June 20 and July 4. After that, everything except perhaps the rough lower Yellowstone east of Livingston will be ready to go.
  • Closures related to low water and high water temperatures are certain on the lower Madison River below Ennis Lake and on the Jefferson River. They are unlikely elsewhere. The Firehole River downstream of the Old Faithful closure zone is ALWAYS too warm to fish after about July 1, and this year will be no exception. Why this water isn’t simply closed from July 4 until Labor Day, I have no idea.
  • Other areas that are unlikely to fish well after noon from mid-July until Labor Day are the Gardner River downstream from Boiling River (a hot spring), as well as on the Gibbon and Madison Rivers in YNP. The lower Gallatin River downstream of Gallatin Gateway also falls into this category.
  • It is possible that low flows combined with heat waves in late July and early August will result in poor fishing conditions after 2-3PM on portions of the Yellowstone River outside YNP, especially points east of Livingston. This will be tied to day-to-day weather. A week of 90+ degree highs and sunshine will mean we need to start at 6AM and quit at 2PM, or fish the Yellowstone in the morning and go elsewhere after lunch. I do not anticipate any mandatory “Hoot Owl” restrictions on the Yellowstone.
Runoff Report, Update on Summer Streamflows, and Summer Fishing Predictions

Runoff Report, Update on Summer Streamflows, and Summer Fishing Predictions

Walter posted a thorough update over at his site. Check it out.

Here are some key takeaways for the PFS operations area:

  • Good winter snowpack is now melting furiously due to near-record temperatures (in the 80s in Livingston), which has everything except the Firehole and Lower Madison blown-out now.
  • Anticipate a brief spring season for the Firehole, Gibbon, and Madison inside YNP, as well as the lower Madison. The Madison basin inside and outside Yellowstone Park has the lowest snowpack in our operations area and it is melting quick.
  • The Yellowstone River outside YNP is likely to fall into fishable shape during the last week of June, with the Salmonfly hatch at the same time.
  • Waters across the northern part of Yellowstone Park will begin falling into shape around June 15-20, with the Yellowstone in the Grand Canyon and the Gardner first. The Black Canyon of the Yellowstone will come into play around June 25 or so, while the Lamar System will probably come in around or after July 4.
  • Slow fishing in late afternoon may occur in late July and August due to warm water temperatures, particularly on low-elevation sections of the Yellowstone east of Livingston, but the Yellowstone has the highest snowpack in our ops area, so except for a few days of “early on, early off” when it’s hot and sunny, we anticipate no other problems. At this time, we do not anticipate any “hoot owl” restrictions on any of our July-September waters. Restrictions are likely on the Jefferson, lower Madison, and other areas we never fish (and no one else fishes) in mid-late summer.
Season Streamflow and Fishing Forecast – May 2 Update (Along with some Corona News)

Season Streamflow and Fishing Forecast – May 2 Update (Along with some Corona News)

Walter made a thorough post about likely summer streamflow and fishing conditions over at his blog. Rather than reposting it and hurting the SEO for both our sits, I’ll just send you over there.

A note on shop ops right now: the shop is open on normal off-season hours of 9-5 daily and 10-4 on Sundays, with occasional unannounced closures. Please follow social distancing guidelines by limiting the shop to one group traveling together at a time. We are available for mail-order business as well as booking guided trips for the high season.